To see the other types of publications on this topic, follow the link: Modifed concrete.
Journal articles on the topic 'Modifed concrete'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 journal articles for your research on the topic 'Modifed concrete.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse journal articles on a wide variety of disciplines and organise your bibliography correctly.
1
Vorozhbiyan, R. M., G. N. Shabanova, and A. N. Korogodskaya. "Refractory concrete based on alumina cement out of low-grade raw materials." NOVYE OGNEUPORY (NEW REFRACTORIES), no. 9 (December 29, 2018): 47–51. http://dx.doi.org/10.17073/1683-4518-2018-9-47-51.
Full textAbstract:
The development results are given for the refractory concretes based on the modifed alumina cement with the using of the chemical industry wastes. The quantitative ratio for the near-gravity materials, the technological factors' influence on the concrete strength, the dependence of its strength properties on the flling aggregate's kind and its curing conditions were defned in the article. It was shown that the physical and mechanical properties of the developed concretes are as good as those of the commercial concretes. According to all technical characteristics this kind of production can be introduced for using as the high temperature vessels' lining material.Ill.6. Ref. 11. Tab. 4.
2
Juan, Pablo Valencia-Villegas, María González Mesa Ana, and Felipe Arbeláez-Pérez Oscar. "Properties of modified concrete with crumb rubber: Effect of the incorporation of hollow glass microspheres." Revista Facultad de Ingeniería, Universidad de Antioquia, no. 98 (April 28, 2020): 59–68. https://doi.org/10.17533/udea.redin.20200473.
Full textAbstract:
In this study, the effect of incorporating hollow glass microspheres (HGM) on the mechanical properties of modified concrete with CR (crumb rubber) was evaluated. Different concrete samples replacing 15% of fine aggregates (total weight of CR + HGM = 15%) were prepared. It was found that the increase in the microsphere content was directly proportional to the slump, compressive strength, and the modulus of elasticity. The increase in the microsphere content was inversely proportional to density. Additionally, we found that in the modified concrete, the width, height and the number of cracks increased as the HGM content increases. The combined sample HGM12.5-CR2.5 (the one with the highest content of microspheres) resulted in concrete with the highest compressive strength of 19.1 MPa, which is 243% stronger than the concrete with only crumb rubber (9.2 MPa). From the XRD results, we were able to detect the presence of different phases formed by hydration during the process of preparing concrete mixtures. The micrographs allowed identifying the fracture in the microspheres during the preparation of the concrete mixtures when they came into contact with the aggregates. The addition of hollow glass microspheres to the mixtures prepared from crumb rubber improved their mechanical properties, and this makes it a potential system that can replace the traditional materials in the production of concrete.
3
Witkowski, Hubert, Janusz Jarosławski, Artur Szkop, Karol Chilmon, Maciej Kalinowski, and Wioletta Jackiewicz-Rek. "The Potential Risk of Nanoparticulate Release from Photocatalytic Pavement Concrete Surface Due to a Simulated Abrasion Load—An Experimental Study." Materials 17, no. 12 (2024): 3022. http://dx.doi.org/10.3390/ma17123022.
Full textAbstract:
The risk of the releasing of nanometric particles from construction materials with nanometric components might be one of the biggest threats to further development of them. One of the possible ingress routes to human organisms is the respiratory system. Therefore, it is crucial to determine the risk of emission of nanometric particles during material usage. In the presented paper, abrasion of mortar samples with nanometric TiO2 was investigated. A special abrasion test setup was developed to reflect everyday abrasion of the concrete surface of pavements. In the study, three TiO2-modifed mortar series (and respective reference series) underwent the developed test protocol and the grains were mobilized from their surface due to the applied load analyzed (granulation, morphology, and chemical composition). For a comparative analysis, an abrasion parameter was developed. Based on the obtained results, the modification of cementitious composites with nanometric TiO2 contributed to a reduction in the emission of aerosols and, therefore, confirmed the compatibility between TiO2 and cement matrix.
4
Shu, Xing Wang, and Ying Zhang. "Mechanical Properties of Modified Epoxy/Rubber Concrete." Materials Science Forum 859 (May 2016): 39–44. http://dx.doi.org/10.4028/www.scientific.net/msf.859.39.
Full textAbstract:
To research the effect of a elastic modifier on the mechanical properties of epoxy/rubber concrete, series of epoxy/rubber concretes were prepared with different elastic modifier content, the relationship between elastic modifier content and stress-strain curve of epoxy/rubber concretes were investigated. Results show: as the increase of elastic modifier content, both the compressive and bending stress-strain curves of epoxy/rubber concretes experience a stage transition of elastic-elastoplasticity-plastic apparently; the slope in the rising and falling section of stress-strain curves are gradually decreased; the peak stress decrease while the corresponding strain and stain energy increase. Content of elastic modifier between 40pbw and 60 pbw is proposed in order to attain better properties of epoxy/rubber concrete. Compared with ordinary concrete and rubberized concrete, Improved epoxy/rubber concrete has better comprehensive mechanical properties and larger rubber content.
5
Grinys, Audrius, Danutė Vaičiukynienė, Algirdas Augonis, Henrikas Sivilevičius, and Rėda Bistrickait. "EFFECT OF MILLED ELECTRICAL CABLE WASTE ON MECHANICAL PROPERTIES OF CONCRETE." Journal of Civil Engineering and Management 21, no. 3 (2015): 300–307. http://dx.doi.org/10.3846/13923730.2015.1005019.
Full textAbstract:
The article focuses on investigation of mechanical and fracture properties of concrete containing electrical cable waste as well as some microstructural features of such concrete. Added to concrete, electrical cable waste reduces the overall concrete bulk density. Compressive, flexural, tensile splitting strengths and elastic modulus decreased when electrical cable waste was admixed to conventional and polymer modified concretes. The best mechanical properties of concrete samples containing electrical cable waste were identified in polymer modified concrete containing 5% of electrical cable waste. Electrical cable waste particles increase the deformability of polymer modified concretes and have almost no influence on normal concrete. Consequently, the optimal amount of electrical cable waste particles can provide concrete with desirable strength that is required for different applications.
6
Balabanov, Vadim, Victor Baryshok, and Nikita Epishkin. "Concrete based on sulfur binder being modified with inorganic additives." MATEC Web of Conferences 212 (2018): 01013. http://dx.doi.org/10.1051/matecconf/201821201013.
Full textAbstract:
The sharply continental climate of the Irkutsk region is characterized by wide temperature intervals throughout the year. The repeated cyclicity of freezing and thawing of building materials in the water-saturated state influences the change in technical characteristics and the durability of concrete products and structures. The concrete products’ features in such climatic conditions create the need for the production of concretes with improved indicators of physical and mechanical properties. The effect of modifying additives on the technological characteristics of sulfur concrete is established. The effect of all elements of sulfur concrete on its strength and frost resistance. The composition of sulfuric concrete is obtained, which meets all the requirements and also has high strength and increased frost resistance. Formulations with a certain ratio of structural sulfuric concrete mixtures were developed. As a result of the use of technical sulfur in the composition of concrete products, the problem of utilizing annually accumulating reserves of technical sulfur is partially solved. The strength properties of sulfuric concretes easily compete with high-quality brands of concrete, special types of concretes that have in their composition additives.
7
Mishutin, Andriy, Kos Zeljko, Grynyova Iryna, and Lucia Chintea. "Durability of Modified Fiber Concrete for Rigid Pavements." Croatian Regional Development Journal 2, no. 1 (2021): 30–40. http://dx.doi.org/10.2478/crdj-2021-0006.
Full textAbstract:
Abstract Modified concretes and fiber concretes for rigid pavements have been investigated. Four-factor experiment was conducted. The amount of Portland cement, polypropylene fiber, metakaolin and polycarboxylate superplasticizer varied in the experiment. All mixtures had the same mobility S2. The active mineral additive metakaolin increases the compressive strength of concrete and its tensile strength in bending. The amount of metakaolin at the level of 15.20 kg/m3 is rational. Due to a decrease in W/C with an increase in the amount of superplasticizer Coral ExpertSuid-5 to 0.9.1%, the compressive strength of concrete increases by 5.7 MPa, the tensile strength in bending increases by 0.5.0.6 MPa. Due to the introduction of polypropylene fiber, the tensile strength of concrete in bending increases by 0.6.0.9 MPa, the frost resistance of concrete increases by 50 cycles. Due to the use of a rational amount of superplasticizer and metakaolin, the frost resistance of concretes and fiber concretes concrete increases by 50-100 cycles. The use of a rational amount of modifiers and fiber reduces the abrasion of concretes by 40.45%. The developed modified fiber concretes of rigid pavements, depending on the amount of Portland cement, have compressive strength from 55 MPa to 70 MPa, tensile strength in bending from 8 MPa to 9.5 MPa, frost resistance from F350 to F450, abrasion from 0.30 to 0.40 g/cm2. Such strength, frost resistance and abrasion resistance allow the use of fiber concretes in pavements with the greatest load and ensures high durability of the material and corresponds to the directions and tasks of the state scientific and technical program “National Transport Strategy of Ukraine for the period up to 2030”
8
Kim, Kwang W., Seung Jun Kweon, Young S. Doh, and Tae-Soon Park. "Fracture toughness of polymer-modified asphalt concrete at low temperatures." Canadian Journal of Civil Engineering 30, no. 2 (2003): 406–13. http://dx.doi.org/10.1139/l02-101.
Full textAbstract:
The fracture toughness of asphalt concrete increases at low temperature and then decreases at temperatures below a certain level. Some polymers are known to have the property of improving the temperature susceptibility of asphalt binder at low temperatures. Therefore, this study evaluated the fracture toughness (KIC) of some polymer-modified asphalt concretes. Low-density polyethylene (LDPE), styrenebutadienestyrene (SBS), and a mixed polymer of LDPE and SBS were used in this study. The fracture toughness KIC of normal asphalt concrete was compared with that of polymer-modified asphalt (PMA) concrete, and the effectiveness of polymer modification against falling values of KIC was evaluated at low temperatures. The results showed that PMA concretes, in general, showed better KIC than normal asphalt concretes, and the temperature at which the highest KIC was obtained was lower than that in the case of normal asphalt concrete. Therefore, the PMA concretes evaluated in this study had better fracture resistance than normal asphalt at low temperatures.Key words: asphalt concrete, polymer-modified asphalt, PMA, fracture toughness, differential thermal contraction, low-temperature damage.
9
Kaprielov, S. S., A. V. Sheynfeld, I. A. Chilin, V. G. Dondukov, and N. M. Selyutin. "Modified concrete: reality and prospects." Bulletin of Science and Research Center of Construction 40, no. 1 (2024): 92–104. http://dx.doi.org/10.37538/2224-9494-2024-1(40)-92-104.
Full textAbstract:
Aim. To review the history of concrete technology over the past 30 years and to analyze current trends in the field.Reality. New concepts and terms that manifest the level of modern science in the field of concrete technology are given. It is shown that the use of complex organomineral modifiers produced on an industrial scale, which are characterized by unique compositions, forms, and processability, allowed Russia to organize promptly mass production of concrete with high performance properties in the amount of about 5 million m3. Examples of construction of unique structures from new modified concretes are presented. The list of such structures includes high-rise buildings, sports facilities, bridges, overpasses, tunnels, etc.Prospects. Priority tasks for further development of concrete technology in Russia have been formulated. Among them are the development and improvement of physical and technical characteristics of concretes; extended use of large-tonnage technogenic wastes in production of concrete mixtures; updating and development of new normative documents for calculation, design, and erection of modern structures with high operational reliability, durability, and aesthetic properties.
10
Al Bakri, A. M. Mustafa, Y. Zarina, M. N. Noor, H. Kamarudin, C. M. Ruzaidi, and A. R. Rafiza. "Study of Concrete Using Modified Polystyrene Coarse Aggregate." Advanced Materials Research 740 (August 2013): 502–6. http://dx.doi.org/10.4028/www.scientific.net/amr.740.502.
Full textAbstract:
Polymer recycling has received a great deal of attention in recent years. At the present time, small percentages of polymer wastes in Malaysia are being recycled. The recycling process has typically consisted of reprocessing the waste material to make other polymeric products or energy recovery from complete combustion. Thus, the development of concrete using non-conventional aggregates, such as polymer waste (especially polystyrene), ceramic waste, or other wastes, has been investigated to determine the comparative properties of the various concretes and the comparative costs. This paper the results of an experimental study in which the coarse aggregates used in conventional concrete were replaced by polystyrene waste aggregate to produce a lightweight material. The proportions of the mixtures were varied to determine the water-cement ratio and the content of polystyrene waste aggregates that provide the best results. The properties of the aggregates were also compared. Strength tests were conducted after the experimental concrete was cured for 28 days, and the experimental results indicated that the strength of the concrete made with polystryene waste aggregate ranged from 14 to 17 MPa. In addition, the density of these concretes ranged between 1467 to 1560 kg/m3, which means that they would be categorized as lightweight concretes. The results also indicated that the workability of the polystyrene waste aggregate concretes was good, and the strength characteristics were comparable to those of conventional concrete.
11
Flohr, Alexander, and Andrea Osburg. "Design and Development of Concretes for Special Rehabilitation Tasks." MATEC Web of Conferences 199 (2018): 07001. http://dx.doi.org/10.1051/matecconf/201819907001.
Full textAbstract:
The requirements for concrete restoration are not only aspects of retrofitting or restoration of bearing capacity but also aspects of preservation of historic structures, such as industrial monuments or civil engineering structures and buildings of the 1960s [1]. Thereby the facsimile replication of the concrete surface is a particular challenge. For the manufacture of delicate and complex structures with restricted accessibility self-compacting concrete (SCC) is well suited [2]. A modification with polymers normally ensures the durability of repair mortars or concretes (PCC) [3]. The combination of PCC and SCC to the Polymer-modified Self-Compacting Concrete (PSCC) for the restoration of historic concrete constructions is the logical consequence, to combine the advantages of both materials and is therefore an interesting alternative to well established materials and methods. Historic concrete constructions are often manufactured of concretes with very stiff consistencies, the so called tamped concretes. So there is a need to develop materials and methods for the rehabilitation of structures made of tamped concrete. For this reason, first investigations have been performed to the recipe development and optimization of its composition, but also properties, furthermore to the design possibilities and how polymers influence the concrete properties. In Germany between 1920 and 1970 industrial buildings and hydraulic structures have been built with concretes, where the content of Portland cement clinker was nearly complete substituted by latent hydraulic materials. The binders of those concretes contain large quantities of blast furnace slag and calcium sulphate and are called super-sulphated cement (SSC). Because of the high sulphate content, the compatibility of concrete structure with SSC is not given to concretes or mortars with other cements. If there is an adequate range of moisture, harmful new formations of phases will occur in the contact zone between SSC-concrete and the other concrete. In the field of rehabilitation PCC are well established. These are polymer-modified mortars or concretes with Portland cement, which are not suitable for the rehabilitation of structures of SSC-concrete. An alternative is the polymer-modification of SSC-concretes with polymers.
12
Nowak-Michta, Aneta. "Additional Porosity as a Side Effect of Polycarboxylate Addition and Its Influence on Concrete’s Scaling Resistance." Materials 13, no. 2 (2020): 316. http://dx.doi.org/10.3390/ma13020316.
Full textAbstract:
A side effect of using modified polycarboxylates to liquefy a concrete mix is additional pores in the concrete. They change the air void system in hardened concretes, and can be used to evaluate the freeze–thaw resistance of concretes. The purpose of this study is to determine the impact of the abovementioned quantitative and qualitative parameters on the freeze–thaw resistance of concretes. The research program was performed on eight sets of air-entraining and non-air-entraining concretes with a variable content of superplasticizer based on modified polycarboxylates. The basic composition of and air-entraining admixture content in the air-entraining concrete mixtures were held constant. Pore structure tests were performed according to EN 480-11. Scaling resistance was determined according to PKN-CEN/TS 12390-9. The results showed that as the content of modified polycarboxylates increased, the pore structure was adversely affected, and, consequently, the air void parameters deteriorated. At the same time, the freeze–thaw resistance of the non-air-entraining concretes decreased. The pores sizes also changed. As the fluidity increased, the specific surface area decreased, and, consequently, the spacing factor increased. The air-entraining concretes, despite the deterioration in the pore structure due to the modified polycarboxylates, were found to be very good quality concretes after 56 freeze–thaw cycles in the presence of 3% NaCl.
13
Gruszczyński, Maciej, and Małgorzata Lenart. "Liquid Penetration Depth and Strength of Concretes Modified with Polymer Admixtures Under the Action of Crude-Oil Products." Materials 12, no. 23 (2019): 3900. http://dx.doi.org/10.3390/ma12233900.
Full textAbstract:
In the present article, the research results of concretes modified with a polymer dispersion of vinyl-benzene and acrylic (PC1) and with a styrene–butadiene dispersion (PC2) are discussed. Concretes were exposed to diesel, non-ethylated fuel, and the standard mixture of light liquids for 1000 h. Concretes modified with polymer dispersions, especially with the styrene–butadiene dispersion (PC2), indicated a smaller degree of liquid penetration into the depth of samples compared to the control concrete. The compressive strength for tested concretes, determined after 1000 h of storage in crude-oil products, in comparison to the strength of samples stored in de-mineralized water was significantly decreased, with the maximum differences equal to 12% for PC2 concrete.
14
Fernandes, Fernando Antonio da Silva, Joseph Salem Barbar, Dayriane do Socorro de Oliveira Costa, and João Adriano Rossignolo. "Experimental Investigation on Interfacial Defect Detection for SCCS with Different Contact NDT Technical." Buildings 13, no. 10 (2023): 2549. http://dx.doi.org/10.3390/buildings13102549.
Full textAbstract:
Knowledge about air-incorporating additives in concrete can favor civil construction with structures that are lighter and more economical. This study investigated the production of concretes with the addition of 1 to 3% of air-entraining additive via the Micro-CT imaging technique. From the microtomography obtained, it was possible to obtain two-dimensional and three-dimensional images of the analyzed samples. The analysis of these images, using FEI Avizo 9.0 image processing software, allowed for obtaining the volumes of concrete, mortar, voids, and porosities of concrete mortars, in addition to the quantities, shapes, and dimensions of pores (voids) present in the samples. The air contents of the concrete with incorporated air were higher than the reference concrete, directly proportional to the additive contents used, and very close to the mixes with the same additive contents. Both the standard and modified mixes showed an increase in air content as the additive content increased. The specific mass of the concretes decreased as the additive content increased in the standard and modified concretes. As for consistency, the air-incorporated concretes showed greater slumps compared to the reference concrete and increased as the additive content increased, demonstrating the action of the air-incorporating additive in improving workability.
15
Medvedeva, G., and A. Lifant'eva A.F. "THE RESEARCH OF MULTILAYER OUTER FENCING INCLUDING MATERIALS USING ASH AND SLAG WASTE OF THERMAL POWER PLANTS." Construction Materials and Products 3, no. 2 (2020): 29–35. http://dx.doi.org/10.34031/2618-7183-2020-3-2-29-35.
Full textAbstract:
the most important direction of resource saving in construction is the widespread use of secondary material resources, which are waste products. The use of secondary products of industry as raw materials for the production of various building materials is very important, because it provides production with rich sources of cheap and, often, already prepared raw materials; lead to lower costs for the production of some building materials, and therefore saves capital investments intended for the construction of buildings and structures; release large areas of land and reduce the impact on the environment. The article deals with heat-insulating and structural-heat-insulating materials, with partial replacement of components by ash-slag waste (ASW): lightweight concretes with broken glass and concretes modified with sulfur. Properties of concretes modified with sulfur are investigated: compressive strength, density and thermal conductivity. In accordance with the obtained properties, a comparative characteristics of the received materials with existing building materials was carried out: sulfur modified concrete and lightweight concrete; lightweight concrete using broken glass and claydite-concrete. Thermophysical calculation of multilayer hencing is made. In each of the options, one of the following materials was selected as a structural and heat-insulating material: lightweight concrete using broken glass and sulfur modified concrete. Also, for each type of hencing, the necessary heat-insulating and structural materials were selected. In the economic part, the cost of the raw materials necessary to obtain 1 m3 of the investigated materials and the cost of 1 m3 of multilayer hencing, which includes the investigated concrete, are calculated.
16
Suddeepong, Apichat, Kongsak Akkharawongwhatthana, Suksun Horpibulsuk, et al. "Polyethylene Terephthalate Modified Asphalt Concrete with Blended Recycled Aggregates: Analysis and Assessment." Civil Engineering Journal 10, no. 11 (2024): 3569–88. https://doi.org/10.28991/cej-2024-010-11-08.
Full textAbstract:
The research study attempts to ascertain the mechanical performance of asphalt concrete, using reclaimed asphalt concrete pavement (RAP) and recycled concrete aggregate (RCA) blends with polyethylene terephthalate (PET) as a modifier. The influence factors were evaluated, including RAP/RCA ratios and PET contents on static and cyclic performances. The static performance was assessed through the indirect tensile strength (ITS) tests, while the cyclic performance was assessed through the indirect tensile resilient modulus (ITMR), indirect tensile fatigue life (ITFL), and wheel tracking tests. Compared to asphalt concrete using natural aggregate (NA), the ITMR of RAP-RCA-PET asphalt concretes was higher when PET contents were between 0.2% and 0.6% for RAP/RCA = 80/20. The ITFL of RAP-RCA-PET asphalt concretes was found to be higher than that of NA asphalt concrete when PET contents ranged from 0.2% to 0.6% for RAP/RCA < 90/10. The ITFL was also higher when PET content was between 0.4% and 0.6% for RAP/RCA = 100/0. RAP-RCA-PET asphalt concretes exhibited lower rut depth than NA asphalt concrete with RAP/RCA = 90/10 and 60/40 at PET contents of 0.4% to 1.0% and with RAP/RCA = 80/20 at PET contents of 0.2% to 1.0%. The RAP/RCA = 80/20 and PET content = 0.6% were found to be the best ingredient in term of both fatigue cracking and rutting resistances. As per the systematic analysis, the fatigue distress models of RAP-RCA-PET asphalt concretes for various PET contents were developed in term of ITFL and tensile strain (𝜀𝑡) relationship and useful for mechanistic design. The results of this research will contribute to promoting RAP-RCA-PET asphalt concrete as a greener material in pavement construction. Doi: 10.28991/CEJ-2024-010-11-08 Full Text: PDF
17
KRUTSKIKH, A. V., V. B. PETROPAVLOVSKAYA, K. S. PETROPAVLOVSKII, and T. B. NOVICHENKOVA. "MODIFIED CEMENT CONCRETE WITH DISCRETE REINFORCEMENT." Building and reconstruction 107, no. 3 (2023): 131–39. http://dx.doi.org/10.33979/2073-7416-2023-107-3-131-139.
Full textAbstract:
Issues related to improving the quality of the operational properties of reinforced concrete and concrete structures by introducing discrete reinforcement - fiber reinforcement are topical tasks of building materials science. The aim of the study was to obtain high-tech concretes with increased flame retardant properties by introducing an optimal combination of fiber reinforcement components. The change in the compressive strength of concrete after fire tests, depending on the percentage of polypropylene fiber, is analyzed. The TSP-27-25 program, developed at the Tver State Technical University, which allows modeling various concrete compositions, was used in the calculation of the control compositions of fiber-reinforced concrete. It has been established that the addition of fiber makes it possible to increase the fire resistance of concrete with an optimal amount of it. An assessment of the strength characteristics of the studied samples after fire exposure is given. The influence of polypropylene fiber content on the nature of concrete destruction is investigated.
18
Paskachev, A. B., T. G. Rzhevskaya, S. A. Stel'makh, E. M. Shcherban, L. D. Mailyan, and A. L. Mailyan. "Comparison of the effectiveness of microsilica modification of lightweight concretes with coarse aggregates from various rocks." Izvestiya vuzov. Investitsii. Stroitelstvo. Nedvizhimost 14, no. 1 (2024): 82–95. http://dx.doi.org/10.21285/2227-2917-2024-1-82-95.
Full textAbstract:
A promising line of research in construction science and practice is the creation of lightweight concretes. They exhibit the so-called strength-density ratio, i. e. a relative characteristic between the strength and weight of the resulting concrete. This ratio simultaneously reflects the maximum possible weight reduction of the structure and its operational reliability. The research aims to compare the effectiveness of microsilica modification of lightweight concretes produced with coarse aggregates from various rocks. The study analyzed the existing scientific literature on lightweight concretes, their formulations, technology, and scientific validity, as well as the structural compatibility of the components used. A comparison was made of the effectiveness of lightweight concrete modification for various formulation technological parameters. The strength of modified lightweight concrete and its strengthdensity ratio changed significantly compared to unmodified lightweight concrete. The strongest effect is achieved when using lightweight granite concrete modified with 9 % of microsilica. As a result, the maximum compressive strength was 55.9 MPa, and the strength-density ratio was 24.3•10-3 MPa•m3/kg compared to other studied concrete compositions. The increase in compressive strength was 17.2 % compared to unmodified lightweight concrete. The strength-density ratio increased by 19.1 % compared to unmodified coarse dense aggregate concrete.
19
Kuźmiński, Kamil, Antoni W. Morawski, and Magdalena Janus. "Application of modified concrete to remove surfactants from water." E3S Web of Conferences 59 (2018): 00016. http://dx.doi.org/10.1051/e3sconf/20185900016.
Full textAbstract:
In these studies two types of modified concretes in photocatalytic mineralization of anionic surfactant sodium dodecylbenzenesulfonate (NaDBS) were used. Commercial TiO2-P25 and nitrogen modified TiO2-N as photocatalysts for concrete modification were employed. The studies were conducted in the special designed reactor which was a simple model of the secondary settler used at the sewage treatment plant. The mineralization of anionic surfactant NaDBS after 18 h of UV light irradiation amounted to 48% for concrete modified by TiO2-P25 and 37% for concrete modified by TiO2-N.
20
Khasanov, Bakhridin, Ruzimurat Choriev, Zukhra Ismailova, Guzal Eshchanova, and Timur Mirzaev. "Study of the strength properties of modified concrete in tension." E3S Web of Conferences 365 (2023): 02004. http://dx.doi.org/10.1051/e3sconf/202336502004.
Full textAbstract:
The resistance of concrete to axial tension is much less than the resistance to compression and is largely determined by the adhesion of its components. The low tensile strength of ordinary concrete is explained by the heterogeneity of its structure and the discontinuity of concrete, which contributes to the development of stress concentration, especially under the action of tensile forces. To increase the tensile strength of concrete, it is necessary to eliminate, first of all, the heterogeneity of the structure of concrete - one of the main reasons for the large dispersion of the results of mechanical tests of this material, which affects the experimental determination of compressive strength. A significant difference between the compressive strength for ordinary concrete indicates a rather large spread of such values. This scatter is explained by the different influence of factors on tension and compression. For example, for ordinary concretes, it was found that with an increase in W/C , the tensile strength decreases, but to a lesser extent than the compressive strength. With an increase in the grade of concrete, the tensile strength increases. High-strength concretes, as a rule, prepared on concrete mixes with low W/C and on clean conditioned aggregates in the form of crushed stone and sand, have an increased density, therefore, they have less variation in strength readings both in compression and at stretching [1-4].
21
Katzer, Jacek, Jacek Halbiniak, Bogdan Langier, Maciej Major, and Izabela Major. "Influence of Varied Waste Ceramic Fillers on the Resistance of Concrete to Freeze–Thaw Cycles." Materials 14, no. 3 (2021): 624. http://dx.doi.org/10.3390/ma14030624.
Full textAbstract:
Our research focused on the influence of fillers obtained from crushed waste materials on the selected properties of concrete composites. The used waste materials were sourced from the production of ceramic tiles, ceramic pots, and sanitary ceramics. We evaluated concretes modified with the addition of 10% (by mass of cement) of different fillers. The properties, including the air content in the fresh concrete mix, consistency, compressive strength, and freeze-thaw resistance were examined. The evaluation of the freeze-thaw resistance was carried out by testing the concrete with the direct method for 150 cycles of freezing and thawing. The characteristics of the concrete porosity structure were assessed using automated digital image analysis. Concretes modified by coarse and fine fillers were characterized by different improvements in the mechanical properties and resistance to cycles of freezing and thawing. Composites with the addition of coarse fillers did not show any significant changes in comparison to the control concrete. An automated digital image analysis of the pore distribution in concrete proved to be an effective tool for the assessment of the freeze–thaw resistance of the concretes in question.
22
Samingthong, Wisanukhorn, Menglim Hoy, Bundam Ro, et al. "Natural Rubber Latex-Modified Concrete with PET and Crumb Rubber Aggregate Replacements for Sustainable Rigid Pavements." Sustainability 15, no. 19 (2023): 14147. http://dx.doi.org/10.3390/su151914147.
Full textAbstract:
There are ongoing research challenges for the addition of the blend of PET and crumb rubber in polymer-modified concretes, which aims to leverage the benefits of both materials. In this study, various percentage combinations of waste aggregates, such as PET and crumb rubber, were used to replace coarse and fine aggregates in natural rubber latex (NRL)-modified concrete. Engineering properties such as compressive and flexural strengths, modulus of elasticity, and toughness obtained from compressive- and flexural stress-strain curves were investigated. Scanning electron microscopy (SEM) analysis was performed to examine the microstructural properties and study the strength development of the studied concretes. The results revealed that the compressive and flexural strengths of NRL-modified concretes with PET and crumb rubber aggregate replacements decreased with increasing replacement ratios. SEM analysis indicated that PET and crumb rubber (hydrophobic and non-polar materials) can affect the microstructure of the studied concrete by creating a weak interface between the aggregate and cement pastes, leading to reduced strength development. With the addition of the NRL additive, the film formation was found to act as a bridge and improve the bond strength of aggregates and hydration products in NRL-modified concrete. Furthermore, the integration of PET and crumb rubber aggregate can enhance the ability of the concrete to absorb energy and improve ductility. It was found that 10% of PET and crumb rubber aggregate replacement can be used for NRL-modified concrete as a rigid pavement, as its mechanical strengths satisfy the requirements set by the Department of Highways (DOH) in Thailand. This research helps repurpose waste materials and reduce the environmental footprint of concrete production.
23
Kastornykh, Lubov, Mikhail Kholodnyak, Igor Osipchuk, and Alexander Kaklyugin. "Modified Concrete Mixes for Monolithic Construction." Materials Science Forum 1043 (August 18, 2021): 81–91. http://dx.doi.org/10.4028/www.scientific.net/msf.1043.81.
Full textAbstract:
The effect of the multifunctional supplement Linamix PCX and mineral fillers of microsilica and expanded clay dust on the characteristics of concrete mixtures pumped by concrete pumps is investigated. The evaluation of highly mobile and self-compacting concrete mixtures’ properties was carried out according to pumpability criteria that simulate the elastic-viscous structured system flow. The physical and mechanical characteristics of the hardened concrete were determined using standard and generally accepted methods. The ability of the modified concrete to resist tensile stresses was determined by the crack resistance coefficient. The water-reducing efficiency of the superplasticizer was evaluated by the specific consumption of cement per unit of concrete strength. The performed studies have established that the polyfunctional superplasticizer Linamix PCX is an effective modifier of concrete mixtures, rheologically compatible with cements of various material composition. A significant effect of the fine aggregate grain size composition on the properties of highly mobile concrete mixtures and the formation of the hardened concrete structure has been revealed. Evaluation of the modified concretes’ strength characteristics showed that it is rational to use the mixtures with Linamix superplasticizer PCX and microsilica, providing high strength concrete with a minimum specific consumption of cement for concreting massive monolithic structures in order to slow down heat generation during concrete hardening.
24
Zhang, Xin Le, Xiao Hui Guo, and Hai Cao. "Experimental Study on Bond Strength between Polymer-Modified Concrete and Plain Concrete." Advanced Materials Research 1030-1032 (September 2014): 1104–7. http://dx.doi.org/10.4028/www.scientific.net/amr.1030-1032.1104.
Full textAbstract:
Polymer-modified concrete is widely used for the rehabilitation of old damaged structures mainly due to its good adhesive performance. The interfacial bond strength between polymer-modified concrete and plain concrete should be measured carefully in order to keep both sides work together. To overcome problems existed in the test of bond strength between two types of concretes, a split apparatus was designed. Experiments on bond strength between plain concrete and polymer-modified concrete with different polymer contents and different interfacial treatments were conducted utilizing the newly devised apparatus, and a series of complete and correct results were obtained. The experimental results indicate that when the surface is treated with 10% polymer solution, the bond strength between plain concrete and polymer-modified concrete with polymer-cement ratio at 15% is better than those in other cases.
25
Urmanshina, Natalia E., and Zinur R. Mukhametzyanov. "Justification for the use of modified concrete for foundations of overpass supports." Concrete and Reinforced Concrete 622, no. 3 (2024): 20–25. http://dx.doi.org/10.37538/0005-9889-2024-3(622)-20-25.
Full textAbstract:
Introduction. The article discusses the possibilities and prospects of using modified concrete for the foundations of overpass supports. The aim is to study the effect of various additives on the sulfate resistance of the foundations of bridge supports and overpasses. Materials and methods. To achieve this goal, tests of reinforced concrete samples were carried out with the introduction of various additives into the concrete mixture. As part of the study, a MasterLife® WP 3760 modifying additive was selected. Using this additive, experiments were conducted with an accelerated assessment of the effect on the sulfate resistance of concrete based on general-purpose Portland cement. In accelerated tests, the sulfate resistance of concretes with the studied additive was performed in comparison with concretes of the same composition prepared on sulfate-resistant and general-purpose Portland cement without additional additives. The water-cement ratio in all tested formulations remained constant. Results. Samples made of general construction cement with the addition of MasterLife® WP 3760 after performing the specified test cycles in a sulfate medium showed a decrease in compressive strength by 3 % from their initial values. The residual strength of concrete samples with MasterLife® WP 3760 additive was 97 %, which exceeds the resistance of concrete to sulfate-resistant cement, the remaining strength of which is 94 %. The MasterLife® WP 3760 additive is a substance that significantly reduces the permeability of concrete due to "blockage" by particles of the substance or neoplasms of pores and capillaries of concrete, these substances due to physical and chemical processes lead to homologation, a decrease in the permeability of concrete, and, as a result, an increase in frost resistance and corrosion resistance. Conclusion. As a result of the action of the MasterLife® WP 3760 additive, the corrosion resistance of concretes and mortars increases, including resistance to sulfate aggression, by reducing water permeability. Thus, it becomes possible to eliminate cracks in concrete with an opening width of up to 0.4 mm and extend the durability of concrete.
26
Kovalenko, V. V. "Structure formation in modified concretes." Science and Transport Progress, no. 41 (August 25, 2012): 157–63. http://dx.doi.org/10.15802/stp2012/8725.
Full textAbstract:
We studied the stages of structure formation in modified concretes, the impact of technological peculiarities of production on the morphology of the structural components of cement crystal hydrate, are shown ways to develop new formulations of concrete with improved physical and mechanical characteristics.
27
Przychodzień, Patrycja, and Jacek Katzer. "Properties of Structural Lightweight Aggregate Concrete Based on Sintered Fly Ash and Modified with Exfoliated Vermiculite." Materials 14, no. 20 (2021): 5922. http://dx.doi.org/10.3390/ma14205922.
Full textAbstract:
Despite the undoubted advantages of using lightweight concrete, its actual use for structural elements is still relatively small in comparison to ordinary concrete. One of the reasons is the wide range of densities and properties of lightweight aggregates available on the market. As a part of the research, properties of concrete based on sintered fly ash were determined. The ash, due to its relatively high density is suitable to be used as a filler for structural concretes. Concrete was based on a mixture of sintered fly ash and exfoliated vermiculite aggregate also tested. The purpose of the research was to determine the possibility of using sintered fly ash as alternative aggregate in structural concrete and the impact of sintered fly ash lightweight aggregate on its physical, mechanical and durability properties. Conducted tests were executed according to European and Polish standards. Created concretes were characterized by compressive strength and tensile strength ranging from 20.3 MPa to 54.2 MPa and from 2.4 MPa to 3.8 MPa, respectively. The lightest of created concretes reached the apparent density of 1378 kg/m3.
28
Bywalski, Czesław, and Mieczysław KamiIński. "RHEOLOGICAL STRAINS IN CONCRETE MODIFIED WITH STEEL FIBRE REINFORCEMENT." Journal of Civil Engineering and Management 19, no. 5 (2013): 656–64. http://dx.doi.org/10.3846/13923730.2013.803497.
Full textAbstract:
This paper discusses the rheological properties of normal (ordinary) strength concrete. The results of tests aimed at determining the creep strains and shrinkage strains in normal strength concretes modified with steel fibre reinforcement are presented. The tests were divided into three groups. Steel fibre reinforced concretes (SFRCs) with a different composition were studied in each of the groups. Hook steel fibres, 50-mm long and 0.8 mm in diameter, were used in the tested SFRCs. The latter had an average compressive strength of 35.17–59.18 MPa and a steel fibre content of 0, 25, 35, 50 and 65 kg per 1 m3 of the concrete mixture respectively. Functional dependences for the increase in shrinkage and creep strains over time are given. The problem of the effect of aggregate grading on creep strains is addressed. Conclusions concerning the rheological deformability of steel fibre reinforced concrete are drawn.
29
Stankiewicz, Natalia. "Modified Protective Concrete." Applied Mechanics and Materials 797 (November 2015): 166–73. http://dx.doi.org/10.4028/www.scientific.net/amm.797.166.
Full textAbstract:
When designing the concrete constructions their adequate durability must be taken into consideration. This property can be ensured by modifying the composition of the concrete mix. This can be done through the implementation of appropriate admixtures and additives into cement composites. This modification can be called material and structural protection. The addition of silica fume or replacing part of the ordinary aggregate by basalt aggregate can change the protective concrete properties. New generation admixtures also can be used for reducing water/binder ratio. In the study, it decided to examine the effects of additives on the technical properties of the protective concretes. The study consisted of determining the optimal composition and modification of cement composites using silica nanoparticles or basalt aggregate. Different contents of cement were also used. Increase in content of basalt aggregates caused an increase in compressive and flexural strength, respectively, approx. 41% and 66%. In addition, partial replacement of the aggregate resulted in a decrease absorption and water resistance.
30
M. Mhaya, Akram, Mohammad Hajmohammadian Baghban, Iman Faridmehr, Ghasan Fahim Huseien, Ahmad Razin Zainal Abidin, and Mohammad Ismail. "Performance Evaluation of Modified Rubberized Concrete Exposed to Aggressive Environments." Materials 14, no. 8 (2021): 1900. http://dx.doi.org/10.3390/ma14081900.
Full textAbstract:
Recycling of the waste rubber tire crumbs (WRTCs) for the concretes production generated renewed interest worldwide. The insertion of such waste as a substitute for the natural aggregates in the concretes is an emergent trend for sustainable development towards building materials. Meanwhile, the enhanced resistance of the concrete structures against aggressive environments is important for durability, cost-saving, and sustainability. In this view, this research evaluated the performance of several modified rubberized concretes by exposing them to aggressive environments i.e., acid, and sulphate attacks, elevated temperatures. These concrete (12 batches) were made by replacing the cement and natural aggregate with an appropriate amount of the granulated blast furnace slag (GBFS) and WRTCs, respectively. The proposed mix designs’ performance was evaluated by several measures, including the residual compressive strength (CS), weight loss, ultrasonic pulse velocity (UPV), microstructures, etc. Besides, by using the available experimental test database, an optimized artificial neural network (ANN) combined with the particle swarm optimization (PSO) was developed to estimate the residual CS of modified rubberized concrete after immersion one year in MgSO4 and H2SO4 solutions. The results indicated that modified rubberized concrete prepared by 5 to 20% WRTCs as a substitute to natural aggregate, provided lower CS and weight lose expose to sulphate and acid attacks compared to control specimen prepared by ordinary Portland cement (OPC). Although the CS were slightly declined at the elevated temperature, these proposed mix designs have a high potential for a wide variety of concrete industrial applications, especially in acid and sulphate risk.
31
Meyer, Yuri Alexandre, Izabella Menezes, Rodrigo Silva Bonatti, Ausdinir Danilo Bortolozo, and Wislei Riuper Osório. "EIS Investigation of the Corrosion Behavior of Steel Bars Embedded into Modified Concretes with Eggshell Contents." Metals 12, no. 3 (2022): 417. http://dx.doi.org/10.3390/met12030417.
Full textAbstract:
This investigation is focused on evaluation of the corrosion behavior of embedded steel bars (SB) into concretes. Conventional and modified concretes with eggshell are prepared. Although the effect of calcium carbonate on mechanical behavior is recognized and reported, their effects as eggshell (ES) particles replacing portions of sand and cement contents are reasonably scarce. Corrosion behavior is evaluated by electrochemical impedance spectroscopy (EIS) and the potentiodynamic polarization technique. Equivalent circuit and porous electrode behavior are also considered. The novelty concerns a promising use of concrete with ES content to maintain corrosion resistance concatenated with reasonable structural properties. For this purpose, three distinct concrete mixtures are proposed, i.e., a reference and two modified concretes. One replaces 10 wt.% with cement and another 10 wt.% with sand content. It is found that porous electrode behavior helps to predict the corrosion mechanism. Finer ES particles in concrete mixture provides a rapidly passivation on rebar. This reflects positively in corrosion current density after long-term immersion. Additionally, an environmentally friendly aspect associated with economical factor constitutes a promise use of the concrete.
32
Nowak-Michta, Aneta. "Salt Scaling Resistance of Variable w/c Ratio Air-Entrained Concretes Modified with Polycarboxylates as a Proper Consequence of Air Void System." Materials 15, no. 17 (2022): 5839. http://dx.doi.org/10.3390/ma15175839.
Full textAbstract:
The values of the air void parameters in hardened concrete (spacing factor L ≤ 0.200 mm and micro air content A300 ≥ 1.5%), determined on the basis of the Powers model, in concretes produced today do not always guarantee the frost resistance of the concrete, especially when in surface impact with the participation of de-icing agents. The literature indicates that the modified polycarboxylates used to liquefy concrete mixes are one of the factors involved in changing the air void system; therefore, the aim of the article was to determine the dependence of the air void parameters and the resistance to scaling of concretes liquefied to a constant consistency by the use of modified polycarboxylates in the spectrum of variability of the ratio w/c = 0.53 ÷ 0.30. In the research program, twelve concrete mixes were made with a constant proportion of aggregate and paste: six air-entrained—with a constant air content of 5.5 ± 0.5%—and six non-air-entrained. The air void parameters were determined in accordance with EN 480-11, while the resistance to scaling was determined in accordance with CEN/TS 12390-9 and assessed according to the criteria of SS 137244. The analysis of the test results showed that liquefaction with modified polycarboxylates did not affect the w/c limit values, enabling obtaining concretes resistant to scaling. They are, respectively, 0.35 in the non-air-entrained concretes and 0.50 in the air-entrained concretes with an air content of 5.5 ± 0.5. Moreover, the commonly used criterion for ensuring the frost resistance of air-entrained concretes, L ≤ 0.200 mm and A300 ≥ 1.5%, requires supplementing with the minimum value of the w/c ≤ 0.50.
33
Barnat-Hunek, Danuta, Piotr Smarzewski, Grzegorz Łagód, and Zbigniew Suchorab. "Evaluation of the Contact Angle of Hydrophobised Lightweight-Aggregate Concrete with Sewage Sludge." Ecological Chemistry and Engineering S 22, no. 4 (2015): 625–35. http://dx.doi.org/10.1515/eces-2015-0037.
Full textAbstract:
Abstract The aim of the research presented in the paper was to evaluate the feasibility of using hydrophobic preparations based on organosilicon compounds for protection treatment of lightweight aggregates modified with municipal sewage sludge. Issues related to the wettability of the surface layer of hydrophobised lightweight-aggregate concrete supplemented with sewage sludge are discussed in the paper. The experimental part of the study is focused on the physical and mechanical characteristics of lightweight-aggregate concrete and the effect of two hydrophobic preparations on the contact angle of the material. The contact angle for lightweight concrete (θw) was determined as a function of time using one measurement liquid. The hydrophobic coatings in the structure of lightweight concrete modified with sewage sludge were shown using electron microscopy. The investigations demonstrated the effectiveness of hydrophobisation of porous lightweight concretes. On the hydrophobic surfaces, the contact angles decreased with time and depended on the preparations used. The results of the research confirm the possibility to produce lightweight aggregate-concretes modified with sewage sludge with appropriate surface protection against external moisture.
34
Lv, Zhengyi, Maohua Zhang, and Yanyu Sun. "Research on The Chloride Diffusion Modified Model for Marine Concretes with Nanoparticles under The Action of Multiple Environmental Factors." Journal of Marine Science and Engineering 10, no. 12 (2022): 1852. http://dx.doi.org/10.3390/jmse10121852.
Full textAbstract:
Marine concrete structures are subject to the action of multiple environments during their service time. This leads to increased deterioration in the durability of marine concretes under the combined action of bending load and dry–wet cycles, salt freeze–thaw cycles, and salt spray erosion. The main reason for the damage of concrete under the action of the above three environments is Cl- attack. The free Cl- content (Cl-f) and the free Cl- diffusion coefficient (Df) of concrete can explain the diffusion of Cl- in concrete. This paper considers the actual environment of marine concrete structures and develops the Cl- diffusion modified model for nano-marine concretes under the action of dry–wet cycles, salt freeze–thaw cycles, and bending load and salt spray erosion. The nano-SiO2, nano-Fe2O3, and nano-Fe3O4 were firstly incorporated into ordinary marine concrete, then the Cl- content of each group of marine concrete was measured at different depths, and the Cl- diffusion coefficients were calculated; finally, the Cl- diffusion modified model was established under different environmental factors. The test results show that the total and free Cl- diffusion coefficients of nano-marine concretes were lower than those of ordinary marine concrete, and the nano-SiO2, nano-Fe2O3, and nano-Fe3O4 of the optimum dosage were 2%, 1%, and 2%, respectively. The fitting results of Cl- content have a good correlation, and the correlation coefficient (R) is basically above 0.98.
35
Abdel-Ghaffar, F., U. F. Kandil, and A. A. Abdel-Khalek. "Nano-modified polymer concrete for infrastructure applications." International Journal of Academic Research 6, no. 1 (2014): 75–84. http://dx.doi.org/10.7813/2075-4124.2014/6-1/a.10.
Full text
36
Niewiadomski, Paweł, and Damian Stefaniuk. "The Effect of Adding Selected Nanoparticles on the Mechanical Properties of the Cement Matrix of Self-Compacting Concrete." Applied Mechanics and Materials 797 (November 2015): 158–65. http://dx.doi.org/10.4028/www.scientific.net/amm.797.158.
Full textAbstract:
The interest in nanomaterials as an addition that improves the properties of concrete has been growing for more than a decade. One of the principal ways of evaluating concretes is the testing of their micro- and nanohardness by means of nanoindentation. This paper presents the results of nanoindentation tests of hardened self-compacting concrete modified with different amounts of nanoparticles. The investigations covered a reference series of self-compacting concrete without any nanoparticle addition and ten concrete series modified with different amounts of SiO2, TiO2and Al2O3powder nanoparticles. An analysis of the test results is carried out and conclusions are drawn.
37
Zajceva, Ljajsjan, Ekaterina Lucyk, Tat’jana Latypova, Valerij Latypov, Pavel Fedorov, and Madina Salamanova. "Influence of the Type of Aggregate from Industrial Waste on Corrosion Resistance of Modified Fine-Grained Concrete." Buildings 11, no. 8 (2021): 352. http://dx.doi.org/10.3390/buildings11080352.
Full textAbstract:
The development and implementation of “green” technologies in the construction sector, which ensure natural resource conservation, reduce harmful emissions and provide utilization of industrial waste, are key issues in material engineering of the XXI century. Extensive research has been devoted to solving these issues, including research in the field of concrete science. Still, the issue of developing concrete compositions with increased corrosion resistance remains much less studied. At the same time, reactive aggregates from industrial waste can have positive effect on durability of concrete, and the best result can be achieved by means of modification of a concrete mixture with highly effective additives. The article presents the research data in two lines—the study of applicability of reactive aggregates from waste products of nonmetallic and ceramic industries, mineral wool production and concrete scrap for production of corrosion-resistant concretes, as well as the assessment of possibility of Portland cement quantity reduction in a concrete mixture on local raw materials due to the introduction of additives based on polycarboxylates. The article presents the research evidence of the effect of dust and clay particles content on the quality of concrete with a polycarboxylate additive. The article describes the studies of corrosion resistance of concrete samples based on production wastes in sulfate environments and under the influence of carbon dioxide. The developed concrete compositions with waste use can be recommended for widespread application, rational use of resources, and production of durable high-quality concretes. The application of additives based on polycarboxylates makes it possible to produce concretes with the reduction of cement consumption in the mixture by 10–20% and decrease in the mode of thermo-wet treatment by two times.
38
Konkol, Janusz. "Fracture Toughness and Fracture Surface Morphology of Concretes Modified with Selected Additives of Pozzolanic Properties." Buildings 9, no. 8 (2019): 174. http://dx.doi.org/10.3390/buildings9080174.
Full textAbstract:
Modern methods of designing and testing concrete must be extended to appropriate material engineering approaches. It is then crucial to link the properties of concrete with its structure described in a quantitative way. The aim of the article was to present the results of research on concretes modified with three additives: Silica fume (SF), activated fluidal ash (FA), and metakaolinite (MK). The concretes were tested for compressive strength, fracture toughness (determining critical stress intensity factor KIcS and elastic modulus E). Also, stereological and fractal tests were performed. The research program covered three separate experiment plans, adopting the water/binder ratio and the additive/binder mass ratio as the independent variables. The results of experiments and their analysis proved a statistically significant relationship between fracture morphology (fractal dimension D) and concrete composition and fracture toughness. A higher fractal dimension was found in concretes with a higher content of cement paste and a lower content of additive. No significant effect of the type of additive used in the above dependence was found. An original method enabling the determination of mechanical properties of concrete with no need for destructive testing has been developed.
39
Szafraniec, Małgorzata, and Danuta Barnat-Hunek. "Evaluation of the contact angle and wettability of hydrophobised lightweight concrete with sawdust." Budownictwo i Architektura 19, no. 2 (2020): 019–32. http://dx.doi.org/10.35784/bud-arch.1644.
Full textAbstract:
The aim of the research presented in the paper was to evaluate the feasibility of using hydrophobic preparations based on organosilicon compounds for protection treatment on the lightweight concrete modified with sawdust. The experimental part of the work concerns the physical and mechanical properties of lightweight concrete and the influence of two hydrophobic agents on the contact angle of the material. Lightweight concrete contact angle (θw) was determined as a time function using one measuring liquid. Water repellent coatings in lightweight concrete structure with the coarse aggregate sawdust (CASD) using electron microscopy were presented. The effectiveness of hydrophobisation of porous lightweight concretes was determined on the basis of the research. For the hydrophobic surface, the contact angle decreased and it depended on the used agents. The lowest contact angle of 40.2° (t=0) was obtained for reference concrete before hydrophobisation and 112.2° after hydrophobisation with a methyl-silicone resin based on organic solvent. The results of scientific research confirm the possibility to produce lightweight concretes modified with CASD with adequate surface protection against external moisture.
40
Zhang, Daming, Fangjin Sun, and Tiantian Liu. "Prediction of Compressive Strength of Geopolymer Concrete Based on Support Vector Machine and Modified Cuckoo Algorithm." Advances in Materials Science and Engineering 2021 (September 25, 2021): 1–14. http://dx.doi.org/10.1155/2021/4286810.
Full textAbstract:
Coal gangue-based geopolymer concrete is an environmentally friendly material made from coal gangue, solid waste from the coal mine. Compressive strength is one of the most important indexes for concretes. Different oxide contents of coal gangue will affect the compressive strength of the geopolymer concrete directly. However, there is little study on the relationship between oxide contents and compressive strength of the geopolymer concrete. Experiments are commonly used methods of determining the compressive strength of concretes, including geopolymer concrete, which is time-consuming and inefficient. Therefore, in the work here, a support vector machine and a modified cuckoo algorithm are utilized to predict the compressive strength of geopolymer concrete. An orthogonal factor is introduced to modify the traditional cuckoo algorithm to update new species and accelerate computation convergence. Then, the modified cuckoo algorithm is employed to optimize the parameters in the support vector machine model. Then, the compressive strength predictive model of coal gangue-based geopolymer concrete is established with oxide content of raw materials as the input and compressive strength as the output of the model. The compressive strength of coal gangue-based geopolymer concrete is predicted with different oxide contents in raw materials, and the effects of different oxide contents and oxide combinations on compressive strength are studied and analyzed. The results show that the support vector machine and the modified cuckoo algorithm are valid and accurate in predicting the compressive strength of geopolymer concrete. And, coal gangue geopolymer concrete compressive strength is significantly affected by oxide contents.
41
Ozyildirim, H. Celik, and Harikrishnan Nair. "Durable Concrete Overlays in Two Virginia Bridges." Transportation Research Record: Journal of the Transportation Research Board 2672, no. 27 (2018): 78–87. http://dx.doi.org/10.1177/0361198118777606.
Full textAbstract:
The purpose of this study was to implement innovative concretes with low permeability and reduced cracking potential in overlays to reduce chloride infiltration into the bridge decks. Two parallel bridges on Route 64 over Dunlap Creek in Alleghany County, Virginia, were selected for this study. For low cracking potential, relatively low water contents, shrinkage reducing admixtures, and lightweight aggregates were used. For low permeability, concretes had supplementary cementitious material and relatively low water–cementitious material ratios. In the overlays, five different materials were used: latex-modified concrete with rapid set cement; silica fume concrete alone; and silica fume concrete with shrinkage reducing admixture, lightweight coarse aggregate, and partial lightweight fine aggregate. A compressive strength of 3,000 psi at 3 days was sought. The performance of the overlay concretes was observed after two to three winters. The overlays used in this study achieved the specified strength and low permeability. There were minimal tight cracks except for one section with the latex-modified concrete with rapid set cement in the left lane of the westbound bridge. The extensive cracks in that section were attributed to plastic shrinkage from adverse weather conditions at placement and the fact that a truck had caught fire in that lane. Silica fume concrete overlays with shrinkage reducing admixture, lightweight coarse aggregate, or lightweight fine aggregate are ready for implementation in the field for low cracking overlays.
42
Yun, K. K., D. H. Kim, and K. J. Kim. "Effect of micro air void system on the permeability of latex-modified concretes with ordinary Portland and very early strength cements." Canadian Journal of Civil Engineering 34, no. 8 (2007): 895–901. http://dx.doi.org/10.1139/l07-011.
Full textAbstract:
This study focused on the impact of the micro air void system on the chloride permeability of latex-modified concretes with ordinary Portland and very early strength cements. The micro air void system was analyzed with the image analysis method. The results of this study will help field engineers and researchers gain a better understanding of the chloride permeability characteristics of latex-modified concretes. The results show that the latex-modified concretes made with both Portland and very early strength cements have more micro air voids, ranging 50 to 500 µm, than ordinary concretes. These small air voids decrease the spacing factor, which is defined as half the average distance that unstable water must travel to reach an escape boundary. The specific surface ranges from 8 to 27 mm–1 and the spacing factor ranges from 275 to 602 µm for ordinary Portland and very early strength cement concretes without and with latex modification. The specific surface tends to decrease as the spacing factor increases. The spacing factors of concretes tend to decrease with latex modification and with very early strength cement. It seems clear that the use of polymer latex in concrete can significantly lower the value of the air void spacing factor by entraining a large number of micro air voids (below 100 µm in diameter). Key words: latex-modified concrete (LMC), micro air void system, chloride permeability, image analysis.
43
Poluektova, Valentina Anatolyevna. "Fine-Grained Polymer-Cement Basalt Fibrous Concrete for 3D Printing." Solid State Phenomena 299 (January 2020): 227–34. http://dx.doi.org/10.4028/www.scientific.net/ssp.299.227.
Full textAbstract:
The construction concrete printing requires new approaches at reinforcement performing. Only successful integration of the existing reinforcement systems will provide for the opportunity to design concrete structures and make objects with the help of additive technologies. The paper dwells upon the issues of possibilities and the efficiency of disperse reinforcement with basalt fibers. It presents a composition of a composite material for 3D printing of a type of fine-grained fibrous concretes with the required technological properties: a necessary plasticity and a high plastic strength for printing large-dimensioned items and structures without timbering by means of extrusion with a high material adhesion between the layers and controlled setting periods. The author studied a possibility to reclaim basalt fiber production wastes as a high-disperse fibrous filler for the reinforcement of polymer-modified concretes. The article provides the dependence of plastic strength on the fiber content in concrete. The authors consider the influence of components and the mechanism of modifying disperse particles of basalt fibrous concrete at obtaining the material for 3D printing. The obtained polymer-modified basal fibrous concrete has a good impact resistance, low water absorption and high crack resistance.
44
Park, Sung-Ki, Jong-Pil Won, and Chan-Gi Park. "Evaluation of Diffusion Property of Latex Modified Concrete." Journal of The Korean Society of Agricultural Engineers 50, no. 4 (2008): 27–37. http://dx.doi.org/10.5389/ksae.2008.50.4.027.
Full text
45
Sivak, Roman. "Modified Cellular Concrete: Structure, Properties, and Potential Applications." Central Ukrainian Scientific Bulletin. Technical Sciences 2, no. 10(41) (2024): 152–60. https://doi.org/10.32515/2664-262x.2024.10(41).2.152-160.
Full textAbstract:
The article proposes a method for the autoclave–free production of ultra–lightweight cellular concrete based on Portland cement, glass waste, and liquid glass. A hardening activator and a gas–forming agent are used to produce a porous material with high thermal insulation properties and water resistance. The proposed concrete can be used as thermal and sound insulation material, as well as for masonry and construction of non–bearing internal walls.
46
Polonina, E. N., S. N. Leonovich, B. M. Khroustalev, E. A. Sadovskaya, and N. A. Budrevich. "Cement-Based Materials Modified with Nanoscale Additives." Science & Technique 20, no. 3 (2021): 189–94. http://dx.doi.org/10.21122/2227-1031-2021-20-3-189-194.
Full textAbstract:
The most common and reliable material without which modern construction is indispensable is concrete. The development of construction production is pushing for new solutions to improve the quality of concrete mix and concrete. The most demanded and significant indicators of a concrete mixture are the compressive strength and mobility of the concrete mixture. Every year, the volume of research on nanomaterials as modifying components of concrete is significantly increasing, and the results indicate the prospects for their use. Nanoparticles with a large specific surface are distinguished by chemical activity, can accelerate hydration and increase strength characteristics due to nucleation and subsequent formation of C–S–H and compaction of the material microstructure. Sol of nanosilica, which can be used instead of microsilica from industrial enterprises, and carbon nanomaterial have a wide reproduction base. This paper presents studies of these types of nanomaterials and the results of their application in cement concrete. Studies have shown that the effect is also observed with the introduction of an additive containing only one type of nanoparticles. The dependence of the obtained characteristics of cement concretes on the content of these nanomaterials has been established. It has been found that the best results were obtained with an additive in which the above-mentioned nanomaterials were used together. Compressive strength of heavy concrete samples, improved by the complex nanodispersed system, was 78.7 MPa, which exceeds the strength of the sample containing the CNT additive in a pair with a super-plasticizer by 37 %. The paper proposes the mechanism for action of the presented complex additive.
47
Khaksari, Zahra, Mohammad Reza Jahani Chegeni, Arman Tavakkol, et al. "Mechanical and Durability Evaluation of Latex Modified Lightweight Concrete." Journal of Civil Engineering and Construction 13, no. 1 (2024): 29–43. http://dx.doi.org/10.32732/jcec.2024.13.1.29.
Full textAbstract:
Modified polymer concretes are popular materials in the construction industry due to their relatively high performance, versatility and stability compared to ordinary cement concrete. In this research, by adding three different latexes, including styrene butadiene rubber, ethylene vinyl acetate and acrylic latex, the mechanical and durability properties of Light weight concrete with Leca aggregates were measured. In this regard, 15 different mixtures are carried out in two laboratory programs. in the first stage, the effect of each latex with 5, 7.5 and 10% percentages with cement are investigated, and in the next stage, the simultaneous effect of latex with Microsilica. It was measured on the properties of lightweight concrete. The results showed that the addition of latex has a significant effect on increasing the durability factors of lightweight concrete several times. With the combination of 7.5% latex and 7% Microsilica, the best compressive strength has been recorded. By using latex, the flexural strength of concrete increased around 30%. Also, the passing charge of the lightweight concrete sample without latex is 4124 coulombs, while the sample containing 10% ethylene vinyl acetate passes 451 coulombs of charge.
48
Qadri, Muhammad Ahmed, Huzaifah Hameed, and Osama Bhutta. "Fresh and Hardened Properties of Styrene Butadiene Rubber (SBR) Modified Concrete." European Journal of Engineering Research and Science 5, no. 4 (2020): 457–61. http://dx.doi.org/10.24018/ejers.2020.5.4.1883.
Full textAbstract:
The durability of concrete has been studied ever since it was first used. Researchers have incorporated several materials to make concrete strong and durable. This research focuses on the infusion of styrene butadiene rubber polymer (SBR) as a partial replacement of cement and studies its effects on fresh and hardened properties of concrete. Samples were prepared using partial replacement of SBR in proportions of 0%, 5%, 10% and 20%. Results showed that the fresh density of concrete decreased with the addition of SBR whereas the trends of workability showed an increase with cement replacement. Compressive strength increased at lower percentage replacements however the flexural and tensile strength increased till 15% SBR addition after which it decreased. The total porosity in terms of water absorption decreased which makes SBR modified concrete feasible for concretes exposed to moist conditions and the decreased porosity would increase its durability against chloride induced corrosion.
49
Qadri, Muhammad Ahmed, Huzaifah Hameed, and Osama Bhutta. "Fresh and Hardened Properties of Styrene Butadiene Rubber (SBR) Modified Concrete." European Journal of Engineering and Technology Research 5, no. 4 (2020): 457–61. http://dx.doi.org/10.24018/ejeng.2020.5.4.1883.
Full textAbstract:
The durability of concrete has been studied ever since it was first used. Researchers have incorporated several materials to make concrete strong and durable. This research focuses on the infusion of styrene butadiene rubber polymer (SBR) as a partial replacement of cement and studies its effects on fresh and hardened properties of concrete. Samples were prepared using partial replacement of SBR in proportions of 0%, 5%, 10% and 20%. Results showed that the fresh density of concrete decreased with the addition of SBR whereas the trends of workability showed an increase with cement replacement. Compressive strength increased at lower percentage replacements however the flexural and tensile strength increased till 15% SBR addition after which it decreased. The total porosity in terms of water absorption decreased which makes SBR modified concrete feasible for concretes exposed to moist conditions and the decreased porosity would increase its durability against chloride induced corrosion.
50
Shohide, Mostafa A., and Mona A. Ahmed. "Influence of Silica Nanoparticles on the Properties of Nanocomposite Based on Epoxy as Concrete Protective Coating." Materials Science Forum 1089 (May 26, 2023): 153–63. http://dx.doi.org/10.4028/p-p961bu.
Full textAbstract:
Concrete structure especially that exposed to aggressive environment is deteriorated leading to damage of concrete buildings. Concrete coating is one of the most effective methods used for concrete protection. In this work epoxy was modified with nanosilica (NS) with different loadings. Epoxy nanosilica (EP-NS) composite was formulated and used as concrete protective coating after evaluate its properties regarding drying time, dry film thickness (DFT), adhesion strength. The coated concretes ware tested as; water absorption, contact angle (hydrophobicity) and chloride diffusion resistance by ion exchange method. Although, durability of coated concretes were examined by determining change in weight and change in compressive strength after immersion in both sulfuric acid and sodium chloride solution separately. The study revealed that, the optimum NS content is 3 % by total weight of coating. The prepared EP-NS coatings have significant protection mechanism for enhancing concrete performance against the postulated aggressive attack. Keywords: protective coating, polymer nanocomposite coating