Journal articles: 'Concrete spalling'

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Peng, Gai Fei, Xu Jie Duan, Xue Chao Yang, and Ting Yu Hao. "Behavior of High Performance Steel-Fiber Concrete Exposed to High Temperature in Terms of Spalling and Permeability." Key Engineering Materials 629-630 (October 2014): 252–58. http://dx.doi.org/10.4028/www.scientific.net/kem.629-630.252.

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An experimental investigation was conducted on behavior of high performance steel-fiber concrete subjected to high temperature, in terms of explosive spalling and permeability. A series of concretes incorporated steel fiber at various dosages were prepared, and further processed to have a series of moisture contents. Explosive spalling tests were conducted on control plain concrete and steel fiber concrete. After explosive spalling tests, each of the specimens that didn’t encounter spalling was sawn into two pieces. Crack observations and permeability tests were conducted on the sawn surfaces. The results prove that steel fiber is efficient to avoid spalling concrete under high temperature. The permeability increases significantly after thermal exposure, while it also exhibits an ascending trend with the increase of moisture content. Therefore it is concluded that steel fiber can play a positive effect on explosive spalling of high performance concrete under high temperature, as well as on permeability after thermal exposure.

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Lublóy, Éva. "The Influence of Concrete Strength on the Effect of Synthetic Fibres on Fire Resistance." Periodica Polytechnica Civil Engineering 62, no. 1 (June 23, 2017): 136–42. http://dx.doi.org/10.3311/ppci.10775.

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Numerous studies have verified that increased concrete strength reduces its resistance to fire, leads to a higher degree of strength reduction and higher chances of spalling of concrete surfaces.The risks of spalling of concrete surfaces can be reduced by adding synthetic polypropylene fibres. Numerous experiments have shown that the risk of spalling of the concrete surface is significantly lower when using short, small diameter fibres of polypropylene synthetic, because the pore structure created by the burning of fibres reduces the risk of cracking.However, the question arises whether other types of fibres of greater diameter and length are still able to prevent spalling of concrete surfaces without drastically reducing the strength and if so, in what range of concrete strength it is true.The experiments are aimed to determine the effects of micro and macro synthetic fibres on the post-fire residual compressive strength, flexural strength and porosity of concrete.Nine kinds of mixture were prepared and tested. Three of them are without fibers (reference concretes) with diverse strength, three with synthetic micro-fibres with diverse strength and three with synthetic macro-fibres of diverse strength. The experiment was conducted with three concretes with different strength. Each type had a reference concrete without fibre reinforcement, one with micro- and one with macro-fibres.

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Zhao, Jie, Jian Jun Zheng, and Gai Fei Peng. "Modeling of Vapor Pressure Build-Up in Heated High-Performance Concrete." Applied Mechanics and Materials 204-208 (October 2012): 3691–94. http://dx.doi.org/10.4028/www.scientific.net/amm.204-208.3691.

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Under high temperature conditions, such as fire, high-performance concrete will undergo material degradation or even spalling. Spalling is the most detrimental to concrete structures. To prevent concrete from spalling, the mechanism should be understood. Since the build-up vapor pressure in concrete is supposed to play a dominant role in spalling, a vapor pressure prediction model is proposed in this paper to quantitatively analyze the vapor pressure, which can be used for the spalling mechanism study.

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Zhao, Jie, Jian Jun Zheng, and Gai Fei Peng. "Fire Spalling Modeling of High Performance Concrete." Applied Mechanics and Materials 52-54 (March 2011): 378–83. http://dx.doi.org/10.4028/www.scientific.net/amm.52-54.378.

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Under high temperature conditions, such as fire, high performance concrete will undergo material degradation or even spalling. Spalling is the most detrimental damage to concrete structures. To prevent concrete from spalling, the mechanism should be understood. In this paper, an anisotropic damage model, in which both the thermal stress and vapor pressure are incorporated, is presented to analyze the spalling mechanism. The spalling phenomenon is studied based on two cases of different moisture contents. It is concluded that when the vapor pressure is present, concrete will behave much more brittlely.

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Hager, Izabela, and Katarzyna Mróz. "Role of Polypropylene Fibres in Concrete Spalling Risk Mitigation in Fire and Test Methods of Fibres Effectiveness Evaluation." Materials 12, no. 23 (November 23, 2019): 3869. http://dx.doi.org/10.3390/ma12233869.

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The explosive behaviour of concrete in fire is observed in rapidly heated concrete. The main factors controlling the occurrence of spalling are related to the material’s low porosity and high density as well as the limited ability to transport gases and liquids. Thus, for high-strength, ultrahigh-strength, and reactive powder concrete, the risk of spalling is much higher than for normal-strength concrete. The paper presents the discussion on the leading hypothesis concerning the occurrence of concrete spalling. Moreover, the methods for spalling prevention, such as polypropylene fibre application, which has been found to be an effective technological solution for preventing the occurrence of spalling, are presented. Various tests and testing protocols are used to screen concrete mixes propensity toward spalling and to evaluate the polypropylene fibres’ effectiveness in spalling risk mitigation. The most effective testing methods were selected and their advantages were presented in the paper. The review was based mainly on the authors’ experiences regarding high performance concrete, reactive powder concrete testing, and observations on the effect of polypropylene fibres on material behaviour at high temperature.

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Lu, Fang Xia, and Mario Fontana. "Concrete Permeability and Explosive Spalling in Fire." Key Engineering Materials 711 (September 2016): 541–48. http://dx.doi.org/10.4028/www.scientific.net/kem.711.541.

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Permeability of concrete is a good indicator of the risk of explosive spalling, concrete with low permeability is more prone to explosive spalling. To study explosive spalling of concrete, experimental tests on the concrete permeability have been carried out at ETH. The influences from temperature and moisture content have been investigated. The permeability of concrete is found to increase with the temperature and to decrease with moisture content. Based on the test results, a permeability model has been proposed. The explosive spalling has been predicted and an engineering boundary permeability for the liability to spalling is recommended to be 2 × 10-17 m2 for a concrete slab heated according to ISO fire curve. The boundary permeability is influenced by moisture content, tensile strength and heating rate.

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Li, Rong Tao. "Application of Fuzzy Pattern Recognition in Spalling Risk Evaluation of Concrete Structures at High Temperature." Advanced Materials Research 919-921 (April 2014): 451–54. http://dx.doi.org/10.4028/www.scientific.net/amr.919-921.451.

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Spalling phenomenon in concrete exposed to high temperatures, e.g. during a fire, can seriously jeopardize the integrity of a whole structure. Spalling risk analysis and evaluation has become the hot topic of research on fire-resistance behavior of concrete structures at present. Based on fuzzy pattern recognition, a model for evaluating spalling risk of concrete structures at high temperature is established according to the factors influencing explosive spalling. The influential factor set is composed of strength, water/cement ratio, fibres content, curing humidity, load level, and heating rate, whose weights are determined by their relative importance. Good agreements between the results of spalling risk prediction and the fire test show the capability of the proposed model in assessing the spalling risk of concrete structures at high temperature, which will provide important reference for the fire resistance design of concrete structures.

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Han, Cheon Goo, Min Cheol Han, Chan Chun Pei, and Seong Hwan Yang. "Effect of Types and Contents of Polymer Resin on Spalling Prevention of High-Strength Concrete Subjected to Fire." Key Engineering Materials 466 (January 2011): 85–95. http://dx.doi.org/10.4028/www.scientific.net/kem.466.85.

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In this study, the fundamental and spalling properties of high-strength concrete were examined, especially when various types and varying content of polymer resin were added. Two types of polymers were used in this study: ethylene vinyl acetate copolymer (EVA-P) and polyvinyl acetate copolymer (PVA-P) as powders and polyvinyl acetate copolymer (PVA-F) and polypropylene copolymer (PP-F) as fibers. Test results showed that the addition of EVA-P and PVA-F to concrete slightly decreased flowability, whereas the addition of PP-F and PVA-P enhanced the viscosity, leading to a remarkable reduction in flowability. The air content of concrete containing EVA-P, PVA-F, and PP-F showed no significant variation. The addition of PVA-P to concrete also caused a slight reduction in compressive strength, whereas the other additives had insignificant effects. After a fire test, the control concrete and concretes with EVA-P, PVA-P, and PVA-F exhibited severe explosive spalling regardless of the dosages. This was because the polymer does not provide sufficient void networks, which is important for vapor evacuation, which enables the release of steam pressure inside the concrete. However, when more than 0.10% of PP-F was added, spalling was effectively prevented. For the residual compressive strength, higher polymer dosage in the concrete produced better results regardless of the polymer type. The powder-type polymers did not contribute to preventing spalling in concrete subjected to fire. This is due to their geometric shape and high melting point. It is concluded that a high aspect ratio and low melting point is critical during polymer selection to prevent spalling in high-strength concrete.

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Hossain, Muhammad Monowar, Safat Al-Deen, Md Kamrul Hassan, Sukanta Kumer Shill, Md Abdul Kader, and Wayne Hutchison. "Mechanical and Thermal Properties of Hybrid Fibre-Reinforced Concrete Exposed to Recurrent High Temperature and Aviation Oil." Materials 14, no. 11 (May 21, 2021): 2725. http://dx.doi.org/10.3390/ma14112725.

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Over the years, leaked fluids from aircraft have caused severe deterioration of airfield pavement. The combined effect of hot exhaust from the auxiliary power unit of military aircraft and spilt aviation oils have caused rapid pavement spalling. If the disintegrated concreted pieces caused by spalling are sucked into the jet engine, they may cause catastrophic damage to the aircraft engine or physical injury to maintenance crews. This study investigates the effectiveness of incorporating hybrid fibres into ordinary concrete to improve the residual mechanical and thermal properties to prevent spalling damage of pavement. Three fibre-reinforced concrete samples were made with micro steel fibre and polyvinyl alcohol fibre with a fibre content of zero, 0.3%, 0.5% and 0.7% by volume fraction. These samples were exposed to recurring high temperatures and aviation oils. Tests were conducted to measure the effects of repeated exposure on the concrete’s mechanical, thermal and chemical characteristics. The results showed that polyvinyl alcohol fibre-, steel fibre- and hybrid fibre-reinforced concrete suffered a 52%, 40% and 26.23% of loss of initial the compressive strength after 60 cycles of exposure to the conditions. Moreover, due to the hybridisation of concrete, flexural strength and thermal conductivity was increased by 47% and 22%. Thus, hybrid fibre-reinforced concrete performed better in retaining higher residual properties and exhibited no spalling of concrete.

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Tian, Kai Pei, Yang Ju, Hong Bin Liu, Jin Hui Liu, Li Wang, Peng Liu, and Xi Zhao. "Effects of Silica Fume Addition on the Spalling Phenomena of Reactive Powder Concrete." Applied Mechanics and Materials 174-177 (May 2012): 1090–95. http://dx.doi.org/10.4028/www.scientific.net/amm.174-177.1090.

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The explosive spalling of high-strength concrete due to fire is a problem that has garnered increasingly widespread attention, particularly the explosive spalling of reactive powder concrete (RPC). For years, based on the vapor pressure mechanism, the addition of fibers has been demonstrated to be somewhat effective in protecting against spalling. However, relevant experiments indicate that fibers are not effective for dense concrete, which is a challenge for the simple vapor pressure mechanism in providing spalling resistance for RPC. The authors found that silica fume plays an important role in the explosive spalling of RPC. Thus, four classes of RPCs with different ratios of silica fume were prepared, and the spalling phenomena and the inner temperature distribution during heating were investigated. The results show that silica fume content has a prominent effect on the spalling process of RPC.

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Miah, Md Jihad, Francesco Lo Monte, Roberto Felicetti, Hélène Carré, Pierre Pimienta, and Christian La Borderie. "Fire Spalling Behaviour of Concrete: Role of Mechanical Loading (Uniaxial and Biaxial) and Cement Type." Key Engineering Materials 711 (September 2016): 549–55. http://dx.doi.org/10.4028/www.scientific.net/kem.711.549.

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Fire poses one of the most severe environmental conditions that can act on concrete structures as an external load and can induce severe damages (cracks, spalling) or even lead to collapse. Fire spalling of concrete is a complex phenomenon, which might occur due to pressure build-up in the pores, thermal and load-induced stresses. In this context, ordinary concrete specimens (B40-II and B40-III: fc28days ≈ 40 MPa) were exposed to standard fire curve (ISO 834-1), while a constant uniaxial or biaxial compressive load was applied. Six different levels of uniaxial compressive stress on cubes and four different levels of biaxial compressive stress on slabs have been investigated. The test results showed that loaded specimens are more susceptible to spalling than unloaded specimens, with increasing amount of spalling for higher values of applied load. It has been found that biaxially loaded specimens are more prone to spalling than uniaxially loaded specimens. B40-II concrete (3% of slag) exhibited higher spalling than the B40-III concrete (43% of slag).

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Choi, Pangil, Lochana Poudyal, Fouzieh Rouzmehr, and Moon Won. "Spalling in Continuously Reinforced Concrete Pavement in Texas." Transportation Research Record: Journal of the Transportation Research Board 2674, no. 11 (September 10, 2020): 731–40. http://dx.doi.org/10.1177/0361198120948509.

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The performance of continuously reinforced concrete pavement (CRCP) in Texas has been quite satisfactory, primarily thanks to the continuous improvements in design and construction. However, severe spalling has been a major problem, and the Texas Department of Transportation (TxDOT) has sponsored several research projects since 1985 to identify solutions for this serious problem. Even though the research efforts were successful in identifying spalling mechanisms, developing a policy that TxDOT could easily implement has been a challenge. To develop a more practical solution to this problem, TxDOT initiated a research study, and the research efforts consisting of identifying CRCP projects with severe and no spalling, obtaining and conducting materials testing on concrete cores from those projects, analyzing the testing data, and performing theoretical analyses to validate the testing results. Among the material properties evaluated, the coefficient of thermal expansion (CTE) of concrete proved to have the best correlation with spalling. Detailed analyses of mechanistic behavior of concrete conducted with an object-oriented finite element program (OOF2) and commercial finite element program verified the reasonableness of the field-testing results. All concrete cores from CRCP with severe spalling had a CTE larger than 5.5 microstrains/°F, whereas no spalling was observed in concrete with a CTE less than that value. Based on this finding, TxDOT now requires the use of coarse aggregate that will produce concrete with a CTE of less than 5.5 microstrains/°F for CRCP construction. It is expected that this implementation will reduce the spalling in CRCP substantially.

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Celeste Blasone, Maria, Dominique Saletti, Edward Andò, Julien Baroth, and Pascal Forquin. "Investigation of Spalling Damage in Ultra-High Performance Concrete Through X-ray Computed Tomography." EPJ Web of Conferences 183 (2018): 03024. http://dx.doi.org/10.1051/epjconf/201818303024.

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Ultra-high performance concretes (UHPC) are increasingly used to build protective structures such as headquarters, nuclear power plants or critical civil engineering structures. However, under impact or contact detonation, concrete is exposed to high-rate tensile loadings that can lead to intense damage modes. Such complex damage modes need to be correctly characterised. When a UHPC sample is subjected to a dynamic tensile loading by means of the spalling technique the post-mortem pattern shows a large number of fractures that cannot be seen with a classical observation of the external face (inner crack network). In the framework of the Brittle’s CODEX chair project, the fracturing process in spalled samples of UHPC is investigated with X-ray computed tomography. The tensile loading is applied thanks to a spalling technique that is based on the reflection of a compressive wave on a free boundary. The concrete samples are entirely scanned using X-ray tomography prior spalling test to identify the initial microstructure, and post spalling test to analyse the damage pattern. Image analysis tools are used in both steps. The main fracturing properties are related to the microstructure of the tested concrete.

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Yu, Xin Meng, Xiao Xiong Zha, and Zhao Hui Huang. "The Influence of Spalling on the Fire Resistance of RC Structures." Advanced Materials Research 255-260 (May 2011): 519–23. http://dx.doi.org/10.4028/www.scientific.net/amr.255-260.519.

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A great many of experiments has shown that reinforced concrete (RC) structures suffered from spalling in fire. However, at present there are still no convincing spalling predicting models available due to the inhomogeneous nature and complicated thermo-hydro-mechanical interactions in concrete at elevated temperatures. In order to evaluate the fire resistance of RC structures which are subjected to concrete spalling, a thermal analysis procedure is developed which considers the effects of spalling on the growth of temperature in RC members. The predicted temperatures are then used to model the structural behaviour. The spalled portion of concrete is modelled as "void", which has no thermal and mechanical properties. A series of parametric studies carried out on RC structural members with different boundary conditions shows that the influence of spalling on fire resistance is very significant apart from the RC slabs subject to higher laterally restraint.

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Chang, Chuan Peng, Shi Wu Huang, Xue Feng Li, Bo Tian, and Zi Yi Hou. "A Study of the Capability for Fire Resistance of Polypropylene Fibre Concrete." Advanced Materials Research 857 (December 2013): 116–23. http://dx.doi.org/10.4028/www.scientific.net/amr.857.116.

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The purpose of this paper is to examine the effect of various polypropylene fibre additions (length and content) to concrete on compressive strength and explosive spalling when subjected to high temperatures, which simulate the building or tunnel fires. The experimental results show that the compressive strength of polypropylene fiber concrete (PFC) and plain concrete decreases with increasing temperature. Fibre content in a certain range has a small effect on the compressive strength of the concrete, therefore the polypropylene (PP) fibers has a great influence on the anti-spalling behavior of concrete under fire loading to ensure the integrity of the structure. Keywords: concrete, polypropylene fibre, high temperature, compressive strength, spalling

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Eratodi, I. Gusti Lanang Bagus, Ali Awaludin, Ay Lie Han, and Andreas Triwiyono. "Evaluation and Study of Prestressed Slab Structure Precast Modular Concrete." MEDIA KOMUNIKASI TEKNIK SIPIL 26, no. 1 (July 30, 2020): 44–51. http://dx.doi.org/10.14710/mkts.v26i1.27765.

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Prestressed precast modular concrete slabs function rigid pavement, supporting vehicle loads above it on subgrade with relatively low bearing capacity. This slab measures 2000 x 850 x 150 mm3 of regular reinforced concrete (old production) or prestressed concrete (new production) quality K-500. After several times of use, damage occurs mainly at the end of the slab in the form of spalling. The objectives of the study and evaluation were: (1) observing damage; (2) material quality data; (3) numerical modeling by taking into account material properties, loading and soil conditions; and (4) providing slab design recommendations including materials and geometrics. The method of study and evaluation of slab damage was done by observing the damage, taking concrete core-case and testing it in the laboratory, and modeling the slab structure with various parameters (soil data, concrete quality and slab geometry). Field observations and analysis results show that concrete slab spalling occurs initially at the edge (850 mm wide) which in turn causes the effectiveness of the pre-tension force to be suboptimal and finally the concrete spalling volume increases. Apart from the frequency of collisions during installation and slab deformation when supporting vehicle loads. Concrete spalling problems also due to inappropriate concrete quality.

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Yang, Juan, and Gai Fei Peng. "The Mechanism of Explosive Spalling and Measures to Resistant Spalling of Concrete Exposed to High Temperature by Incorporating Fibers: A Review." Advanced Materials Research 168-170 (December 2010): 773–77. http://dx.doi.org/10.4028/www.scientific.net/amr.168-170.773.

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Many experimental researches have been conducted on explosive spalling performance of concrete of high-strength / high performance concrete (HSC/HPC). This paper summarizes two main explosive spalling mechanisms (Vapor pressure build-up mechanism and Thermal stress mechanism) of concrete at elevated temperature, and also presents the measures to resistant the explosive spalling, i.e. by incorporating fibers (polypropylene fiber(PPF), steel fiber(SF) and hybrid fiber of the first two). Finally, the further studies of both the mechanism and the measures are proposed. Also, the preliminary study of ultra high-strength concrete (UHSC) on fire-resistance are mentioned.

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Zollinger, Dan G., Sanjaya P. Senadheera, and Tianxi Tang. "Spalling of Continuously Reinforced Concrete Pavements." Journal of Transportation Engineering 120, no. 3 (May 1994): 394–411. http://dx.doi.org/10.1061/(asce)0733-947x(1994)120:3(394).

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Xiong, Wei, Bo Wu, and Bo Wen. "Spalling of concrete cover of cyclically loaded columns and fire behaviour of columns with concrete spalling." Structure and Infrastructure Engineering 12, no. 12 (March 8, 2016): 1537–52. http://dx.doi.org/10.1080/15732479.2016.1151055.

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Zhou, Mingliang, Wen Cheng, Hongwei Huang, and Jiayao Chen. "A Novel Approach to Automated 3D Spalling Defects Inspection in Railway Tunnel Linings Using Laser Intensity and Depth Information." Sensors 21, no. 17 (August 25, 2021): 5725. http://dx.doi.org/10.3390/s21175725.

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The detection of concrete spalling is critical for tunnel inspectors to assess structural risks and guarantee the daily operation of the railway tunnel. However, traditional spalling detection methods mostly rely on visual inspection or camera images taken manually, which are inefficient and unreliable. In this study, an integrated approach based on laser intensity and depth features is proposed for the automated detection and quantification of concrete spalling. The Railway Tunnel Spalling Defects (RTSD) database, containing intensity images and depth images of the tunnel linings, is established via mobile laser scanning (MLS), and the Spalling Intensity Depurator Network (SIDNet) model is proposed for automatic extraction of the concrete spalling features. The proposed model is trained, validated and tested on the established RSTD dataset with impressive results. Comparison with several other spalling detection models shows that the proposed model performs better in terms of various indicators such as MPA (0.985) and MIoU (0.925). The extra depth information obtained from MLS allows for the accurate evaluation of the volume of detected spalling defects, which is beyond the reach of traditional methods. In addition, a triangulation mesh method is implemented to reconstruct the 3D tunnel lining model and visualize the 3D inspection results. As a result, a 3D inspection report can be outputted automatically containing quantified spalling defect information along with relevant spatial coordinates. The proposed approach has been conducted on several railway tunnels in Yunnan province, China and the experimental results have proved its validity and feasibility.

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Nguyen, Kate TQ, Tuan Ngo, Priyan Mendis, and David Heath. "Performance of high-strength concrete walls exposed to fire." Advances in Structural Engineering 21, no. 8 (September 26, 2017): 1173–82. http://dx.doi.org/10.1177/1369433217732500.

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High-strength concrete is becoming very popular around the world due to its many advantages over normal-strength concrete. There are significant behavioural differences between high-strength concrete and normal-strength concrete, most notably the brittleness and sudden spalling under elevated temperatures, whereby pieces of hardened concrete explosively dislodge. Although all high-rise and even many medium-rise buildings have high-strength concrete walls, the spalling of high-strength concrete walls in fire has generally been ignored by the designers and the fire resistance of walls has been calculated using the rules specified for normal-strength concrete. Catastrophic failures could occur due to this ignorance of an important issue. Major design codes including the American and Australian Codes do not cover spalling adequately. Even the Eurocode rules are based on limited research. After a brief discussion on the present design practice, this article presents a summary of spalling research. The relevant results from a comprehensive study conducted at the University of Melbourne are briefly discussed. The authors are not aware of any other comprehensive research projects covering the fire behaviour of normal-strength concrete and high-strength concrete walls exposed not only to standard fires but also hydrocarbon fires. The results showed that spalling in high-strength concrete is more significant when subjected to hydrocarbon fire compared to normal-strength concrete. The level of compressive load on the panels was also found to have a significant effect on the fire performance of the high-strength concrete panels. The finite analysis element program, ANSYS, was used to model the concrete walls subjected to load and fire (both ISO834 Standard fire and hydrocarbon fire). The test results were used to validate the computer model.

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Zhang, Li, Ya Wei, Francis Tat Kwong Au, and Jing Li. "Experimental study of two-way post-tensioned flat slabs in fire." Journal of Structural Fire Engineering 9, no. 3 (September 10, 2018): 237–51. http://dx.doi.org/10.1108/jsfe-01-2017-0016.

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Purpose This study aims to investigate the influence of tendon layout, pre-stressing force, bond condition and concrete spalling on the structural behaviour of two-way post-tensioned flat slabs at elevated temperatures. Design/methodology/approach Fire tests of four scale specimens of two-way post-tensioned concrete flat slabs were performed and analysed. Three of them were provided with bonded tendons, while the other was unbonded for comparison. The fabrication of specimens, phenomena observed during testing, temperature distributions, deflections and occurrence of concrete spalling were examined. Findings Different degrees of concrete spalling observed at the soffit had significant effects on the temperature distribution and stress redistribution. This was the major reason for the progressive concrete spalling observed, resulting in loss of structural integrity and stiffness. Originality/value The structural behaviour of two-way post-tensioned concrete flat slabs at elevated temperatures is less understood compared to their one-way counterparts. Therefore, the present study has focused on the structural behaviour of two-way post-tensioned concrete flat slabs with bonded tendons in fire, a field in which relatively little information on experimental work can be found.

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Cherif, Guergah, Dimia Mohamed Salah, and Benmarce Abdelaziz. "Numerical Modelling of One-Way Reinforced Concrete Slab in FireTaking Into Account of Spalling." Civil Engineering Journal 7, no. 3 (March 3, 2021): 477–87. http://dx.doi.org/10.28991/cej-2021-03091667.

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This paper presents a study of the behaviour of Reinforced Concrete (RC) slabs subjected to severe hydrocarbon fire exposure. In which the spalling phenomena of concrete is to be considered. The hydrocarbon curve is applicable where small petroleum fires might occur, i.e. car fuel tanks, petrol or oil tankers, certain petro-chemical facilities, tunnels, parking structures, etc. Spalling is included using a simplified approach where elements with temperatures higher than 400 °C are assumed to occur and the corresponding thermo-mechanical response of RC slabs is evaluated. The nonlinear finite element software SAFIR has been used to perform a numerical analysis of the spalling risk, by removing layers of concrete covering when a set of spalling criteria is checked. The numerical results obtained by finite element analysis of the temperature distribution within the slab and mid-span deflection were compared with published experimental data. Predictions from the numerical model show a good agreement with the experimental data throughout the entire fire exposure to the hydrocarbon fire. This shows that this approach (layering procedure) is very useful in predicting the behaviour of concrete spalling cases. Doi: 10.28991/cej-2021-03091667 Full Text: PDF

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Hager, Izabela, Katarzyna Mróz, and Tomasz Tracz. "Concrete propensity to fire spalling: testing and observations." MATEC Web of Conferences 163 (2018): 02004. http://dx.doi.org/10.1051/matecconf/201816302004.

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This article presents results of fire spalling tests on small concrete slabs and studies of material parameters that may increase its occurrence. Experimental techniques enabling to study and determination of material features are presented and discussed. Experimental studies on spalling behaviour of elements were carried out on seven different concrete mixes with constant content of cement paste and mortar. Research aimed at determining influence of the following parameters: w/c ratio (0.30; 0.45; 0.60), cement type (CEM I, CEM III) and type of aggregates (riverbed gravel, granite, basalt) on fire concrete spalling. Paper discusses also the influence of cold rim that forms while testing slab-like element is subjected to one-side heating.

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Yu, Xinlu, Yingqian Fu, Xinlong Dong, Fenghua Zhou, and Jianguo Ning. "An Improved Lagrangian-Inverse Method for Evaluating the Dynamic Constitutive Parameters of Concrete." Materials 13, no. 8 (April 16, 2020): 1871. http://dx.doi.org/10.3390/ma13081871.

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The dynamic constitutive behaviors of concrete-like materials are of vital importance for structure designing under impact loading conditions. This study proposes a new method to evaluate the constitutive behaviors of ordinary concrete at high strain rates. The proposed method combines the Lagrangian-inverse analysis method with optical techniques (ultra-high-speed camera and digital image correlation techniques). The proposed method is validated against finite-element simulation. Spalling tests were conducted on concretes where optical techniques were employed to obtain the high-frequency spatial and temporal displacement data. We then obtained stress–strain curves of concrete by applying the proposed method on the results of spalling tests. The results show non-linear constitutive behaviors in these stress–strain curves. These non-linear constitutive behaviors can be possibly explained by local heterogeneity of concrete. The proposed method provides an alternative mean to access the dynamic constitutive behaviors which can help future structure designing of concrete-like materials.

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Hajihasani, Nadia, and Norhisham Bakhary. "Detection of Concrete Spalling Using Changes in Modal Flexibility." Advanced Materials Research 163-167 (December 2010): 2598–602. http://dx.doi.org/10.4028/www.scientific.net/amr.163-167.2598.

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This paper presents a study in the effect of spalling to dynamic parameters such as natural frequencies and mode shapes. Numerical example of a slab is used as an example in this study. The slab will be modelled using ANSYS 11.0 and various types of spalling are imposed. The changes of vibration parameters are monitored and compared. To compare the sensitivity of modal parameters to spalling is determined using the flexibility method. Based on the results it is found that by incorporating mode shapes using flexibility method, damage location and severity can be obtained.

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Yoo, S. H., S. W. Shin, and I. K. Kim. "Optimum Dosage of PP Fiber for the Spalling Control of High Strength Reinforced Concrete Columns." Key Engineering Materials 348-349 (September 2007): 621–24. http://dx.doi.org/10.4028/www.scientific.net/kem.348-349.621.

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Spalling is defined as damages to concrete exposed to high temperature during fire, causing cracks and localized bursting of small pieces of concrete. As the concrete strength increases, the degree of damage caused by spalling becomes more serious due to impaired permeability. It has been reported that polypropylene(PP) fiber has an important role in protecting concrete from spalling, and the optimum dosage of PP fiber is 0.2%. However, this result was based on the fire test of non-reinforced concrete specimens. The high-temperature behavior of highstrength reinforced concrete columns with various concrete strength and various quantity of PP fibers is investigated in this study. The results revealed that the ratio of unstressed residual strength of columns increased as the concrete strength increased and as the quantity of PP fiber increased from 0% to 0.2% the residual strength of columns increase. However, the effect of PP fiber quantity on residual strength of column was barely above 0.2%.

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He, Ke-cheng, Rong-xin Guo, Qian-min Ma, Feng Yan, Zhi-wei Lin, and Yan-Lin Sun. "Experimental Research on High Temperature Resistance of Modified Lightweight Concrete after Exposure to Elevated Temperatures." Advances in Materials Science and Engineering 2016 (2016): 1–6. http://dx.doi.org/10.1155/2016/5972570.

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In order to improve the spalling resistance of lightweight aggregate concrete at high temperature, two types of modified materials were used to modify clay ceramsite lightweight aggregates by adopting the surface coating modification method. Spalling of the concrete specimens manufactured by using the modified aggregates was observed during a temperature elevation. Mass loss and residual axial compressive strength of the modified concrete specimens after exposure to elevated temperatures were also tested. Concrete specimens consisting of ordinary clay ceramsites and crushed limestone were manufactured as references for comparison. The results showed that the ordinary lightweight concrete specimens and the crushed limestone concrete specimens were completely spalled after exposure to target temperatures above 400°C and 1000°C, respectively, whereas the modified concrete specimens remained intact at 1200°C, at which approximately 25% to 38% of the residual compressive strength was retained. The results indicated that the modified lightweight concrete specimens have exhibited superior mechanical properties and resistance to thermal spalling after exposure to elevated temperatures.

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Peng, Gai Fei, and Yan Teng. "Fire Resistance of Ultra-High-Strength Concrete: a Review." Key Engineering Materials 477 (April 2011): 333–39. http://dx.doi.org/10.4028/www.scientific.net/kem.477.333.

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This paper presents a review of advances in research on fire resistance of high-strength concrete (HSC) and ultra-high-strength concrete (UHSC). Further research needs in the near future on UHSC, especially on reactive powder concrete (RPC), are also discussed. It is commonly recognized that HSC suffers strength loss in a manner basically similar to that of normal strength concrete. But the main problem of HSC is explosive spalling under high temperature, which can be solved by employing either polymer fiber or steel fiber. Since RPC200 is a type of RPC which has been successfully prepared in many counties and is to be applied to engineering practice, fire resistance of RPC200 needs a series of investigations urgently. The objectives of such investigations are to restrain explosive spalling and minimizing spalling probability, so as to ensure satisfactory fire resistance of RPC. It is expected that a research will be carried out on explosive spalling behavior, fracture properties, and micro-structure, to establish a mechanism as well as technical measures for improving fire resistance of RPC.

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Lim, Bryan, and Pei Jun Hong. "Sprayed-On Polymer as Concrete Spall Shield." Solid State Phenomena 136 (February 2008): 145–52. http://dx.doi.org/10.4028/www.scientific.net/ssp.136.145.

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Concrete when subjected to a blast loading from a close-in detonation will experience spalling due to formation of tension waves on the opposite face of the concrete panel. The spalled concrete may be ejected at high velocity causing undesirable effects to occupants. Tests using 1/2kg TNT blocks were conducted on 100mm thick concrete panels to study the effects of spalling and whether the spalled materials can be arrested using a sprayed-on polymeric coating. From the tests, it was observed that without the sprayed-on polymeric coating, extensive spalling occurred. However, with just a 3-4mm thick layer of sprayed-on polymer, the spalled materials were arrested and contained. Numerical models of the reinforced concrete slab were created using Autodyn 2D and the results of the simulation were compared to observations from the tests. There was good correlation between the test results and the simulation results as the size of the crater, both front and back, on the concrete slab were rather similar.

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Siemon, Matthias, and Jochen Zehfuß. "Behavior of structural tunnel elements exposed to fire and mechanical loading." Journal of Structural Fire Engineering 9, no. 2 (June 11, 2018): 138–46. http://dx.doi.org/10.1108/jsfe-01-2017-0020.

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Purpose Incidents like the fire in the Channel Tunnel, where severe concrete spalling was determined, have led to requirements in limiting the spalling depth and involved zone to local and compatible magnitudes. Because the prevention of critical concrete spalling was also significant for the validity of the load-carrying capacity calculation for an existing railway tunnel, this paper aimed to investigate the spalling behavior of two contemplable concrete mixtures. The large-scale tests should show the load-carrying capacity over the whole duration of the fire exposure respecting all thermal and mechanical loads considered in the calculations. Design/methodology/approach In this paper, the fire behavior of two concrete mixtures for an existing railway tunnel are investigated. Small-scale tests prior to the main tests were conducted to identify an appropriate concrete mixture for the large-scale tests. During the large-scale tests, a tunnel segment is loaded with horizontal and vertical loads derived from a calculation taking into account the existing boundary conditions. Resulting restraint forces were calculated using the soil stiffness and tunnel fire design curve as fire scenario and applied via hydraulic jacks. To avoid additional restraint forces during the experiment, thermal strains due to fire exposure were allowed. Findings The results of the small-scale tests did not allow for a clear statement whether one concrete mixture would perform better regarding the spalling behavior. The two large-scale tests showed different results regarding the spalling behavior. Over the whole duration of fire exposure, the first test specimen remains nearly undamaged. During the test of the second specimen, spalling started about 3 min after burner activation. Because of the results, a suggestion for the concrete mixture of the first test was made, and this mixture was then used for the redevelopment of the existing railway tunnel. Originality/value The test setup was capable of incorporating all relevant boundary conditions for the analysis of an existing railway tunnel as part of an important north – south connection. The results have shown that a fire-proof construction is possible by adding polypropylene fibers to the concrete mixture. Additionally, it was possible to avoid the mounting of expensive and time-consuming fire protection measures like the installation of thermal insulation boards.

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Wu, Hangbin, Xingran Ao, Zhuo Chen, Chun Liu, Zeran Xu, and Pengfei Yu. "Concrete Spalling Detection for Metro Tunnel from Point Cloud Based on Roughness Descriptor." Journal of Sensors 2019 (May 2, 2019): 1–12. http://dx.doi.org/10.1155/2019/8574750.

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Automatic concrete spalling detection has become an important issue for metro tunnel examinations and maintenance. This paper focuses on concrete spalling detection research with surface roughness analysis based on point clouds produced by 3D mobile laser scanning (MLS) system. In the proposed method, at first, the points on ancillary facilities attached to tunnel surface are considered as outliers and removed via circular scan-line fitting and large residual error filtering. Then, a roughness descriptor for the metro tunnel surface is designed based on the triangulated grid derived from point clouds. The roughness descriptor is generally defined as the ratio of surface area to the projected area for a unit, which works well in identifying high rough areas on the tunnel surface, such as bolt holes, segment seams, and spalling patches. Finally, rough area classification based on Hough transformation and similarity analysis is performed on the identified areas to accurately label patches belonging to segment seams and bolt holes. After removing the patches of bolt holes and segment seams, the remaining patches are considered as belonging to concrete spalling. The experiment was conducted on a real tunnel interval in Shanghai. The result of concrete spalling detection revealed the validity and feasibility of the proposed method.

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Wang, Shimin, Chuankun Liu, Gaoyu Ma, Songyu Cao, Junbo Zhang, Daiyue Lu, and Chuan He. "Experimental Investigation on the Influence of Regional Concrete Spalling on Shield Tunnel Segments." Advances in Civil Engineering 2019 (June 27, 2019): 1–15. http://dx.doi.org/10.1155/2019/1829124.

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Based on the field investigation and analysis, the mechanical characteristics of segment structure in shield tunnels are compared and analyzed under the circumstances of different concrete spalling region by the method of similarity model experiment. Through data analysis of acoustic emission, the results for displacement and internal force of shield tunnel segments are clarified on the segment lining, the influential rule of load bearing capacity is also determined, and the deformation and stress for the different concrete spalling region are described as well. The corresponding research results indicate that range for elastic bearing stage is enlarged while it is narrowed for plastic bearing stage, the convergence and deformation and the accumulated event numbers for acoustic emission on critical instability point are obviously increasing, and the process of damage and failure tends to be sudden for segment lining structure. The ultimate bearing capacity of the damaged segment lining obviously decreases due to regional concrete spalling; to be more specific, the reduction rate for ultimate bearing capacity becomes 6%, 6%, and 13%, respectively, when the range of concrete spalling reaches 45°, 60°, and 75°.

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Rohden, Abrahão Bernardo, Jessica Regina Camilo, Rafaela Cristina Amaral, Estela Oliari Garcez, and Mônica Regina Garcez. "Effects of Plastic Waste on the Heat-Induced Spalling Performance and Mechanical Properties of High Strength Concrete." Materials 13, no. 15 (July 23, 2020): 3262. http://dx.doi.org/10.3390/ma13153262.

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This paper investigates a potential application of hard-to-recycle plastic waste as polymeric addition in high strength concrete, with a focus on the potential to mitigate heat-induced concrete spalling and the consequent effects on the mechanical properties. The waste corresponds to soft and hard plastic, including household polymers vastly disposed of in landfills, although technically recyclable. Mechanical and physical properties, cracking, mass loss, and the occurrence of spalling were assessed in high strength concrete samples produced with either plastic waste or polypropylene fibers after 2-h exposure to 600 °C. The analysis was supported by Scanning Electron Microscopy and X-Ray Computed Tomography images. The plastic waste is composed of different polymers with a thermal degradation between 250 to 500 °C. Polypropylene (PP) fibers and plastic waste dispersed in concrete have proved to play an essential role in mitigating heat-induced concrete spalling, contributing to the release of internal pressure after the polymer melting. The different morphology of plastic waste and polypropylene fibers leads to distinct mechanisms of action. While the vapor pressure dissipation network originated by polypropylene fibers is related to the formation of continuous channels, the plastic waste seems to cause discontinuous reservoirs and fewer damages into the concrete matrix. The incorporation of plastic waste improved heat-induced concrete spalling performance. While 6 kg/m3 of plastic increased the mechanical performance after exposure to high temperature, the incorporation of 3 kg/m3 resulted in mechanical properties comparable to the reference concrete.

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Wang, Ligang, and Dan G. Zollinger. "Mechanistic Design Framework for Spalling Distress." Transportation Research Record: Journal of the Transportation Research Board 1730, no. 1 (January 2000): 18–24. http://dx.doi.org/10.3141/1730-03.

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Spalling is a distress form in concrete pavements that often manifests as the breakdown of the joint of a slab within 15 cm (6 in.) of the joint or crack and can occur at both longitudinal and transverse joints. Efforts have been under way at Texas A&M University to formulate mechanistic spalling models derived from data gathered in recent Texas Department of Transportation studies related to spall development. Extensive field studies have led to the establishment of a spalling mechanism consisting of a step-by-step process that can be characterized with engineering mechanics. These findings indicate that spalling is the result of damage initiated in the form of a shear delamination that is oriented parallel to and at a shallow depth below the surface of the pavement. Conditions necessary for formation of the delaminations include low interfacial strength between the aggregate and mortar and sufficient evaporation of pore water from the hydrating concrete, resulting in differential drying shrinkage near the pavement surface. Delaminations have been noted to initiate early in the life of the pavement and, once formed, extend later into spalls as a result of incompressibles, freeze-thaw cycles, traffic loading, and other such effects. A design framework for delamination formation and subsequent spalling development is presented in a practical format in which to mechanistically design concrete pavement systems relative to spalling distress.

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GIL, A. M., B. FERNANDES, F. L. BOLINA, and B. F. TUTIKIAN. "Experimental analysis of the spalling phenomenon in precast reinforced concrete columns exposed to high temperatures." Revista IBRACON de Estruturas e Materiais 11, no. 4 (August 2018): 856–75. http://dx.doi.org/10.1590/s1983-41952018000400011.

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Abstract Among the processes that involve the degradation of concrete structures subject to the high temperatures of a fire there is the spalling phenomenon. Its mechanisms are related to the thermal stress of the materials dilatations and pore pressure the process of vaporization of water during heating. The factors that influences in its occurrence are related to concrete properties, structural member characteristics or the exposure conditions, and their parameters are not clearly known yet. This paper aimed to study the influence of three concrete mixtures, four coating thicknesses and two bars diameters of longitudinal reinforcement in the spalling phenomena exposed to ISO 834 fire curve. The characterization of concrete were performed either of the axial compression strength tests, water absorption by capillary and mercury intrusion porosimetry, besides the fire resistance tests in real-scale specimens. It was concluded that the diameter of the bar does not have influence, while the mixture and the concrete cover thickness does. More spalling was recorded for the columns with thicker concrete cover and concrete compressive strength at 61,9 MPa, and although higher strength concrete have less permeability, this characteristic can be balanced with the higher tensile strength of this type of concrete.

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Kodur, Venkatesh, and Monther Dwaikat. "Fire-induced spalling in reinforced concrete beams." Proceedings of the Institution of Civil Engineers - Structures and Buildings 165, no. 7 (July 2012): 347–59. http://dx.doi.org/10.1680/stbu.11.00013.

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Hertz, K. D. "Limits of spalling of fire-exposed concrete." Fire Safety Journal 38, no. 2 (March 2003): 103–16. http://dx.doi.org/10.1016/s0379-7112(02)00051-6.

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Smith, Frederick P. "Concrete spalling: controlled fire tests and review." Journal of the Forensic Science Society 31, no. 1 (January 1991): 67–75. http://dx.doi.org/10.1016/s0015-7368(91)73119-8.

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Rollings, Raymond S. "Joint Spalling in Newly Constructed Concrete Pavements." Journal of Performance of Constructed Facilities 12, no. 3 (August 1998): 137–44. http://dx.doi.org/10.1061/(asce)0887-3828(1998)12:3(137).

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Rollings, Raymond S., Jerry P. Burkes, Michael I. Hammons, G. Sam Wong, and Marian P. Rollings. "Investigation of Joint Spalling on Concrete Runway." Journal of Performance of Constructed Facilities 12, no. 1 (February 1998): 12–19. http://dx.doi.org/10.1061/(asce)0887-3828(1998)12:1(12).

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Jansson, R. "Fire spalling of concrete – A historical overview." MATEC Web of Conferences 6 (2013): 01001. http://dx.doi.org/10.1051/matecconf/20130601001.

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Foglar, M., and M. Kovar. "Spalling of concrete subjected to blast loading." MATEC Web of Conferences 6 (2013): 07005. http://dx.doi.org/10.1051/matecconf/20130607005.

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Phan, Long T. "Pore pressure and explosive spalling in concrete." Materials and Structures 41, no. 10 (January 18, 2008): 1623–32. http://dx.doi.org/10.1617/s11527-008-9353-2.

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Zhang, L., S. S. Hu, D. X. Chen, Z. Q. Yu, and F. Liu. "An Experimental Technique for Spalling of Concrete." Experimental Mechanics 49, no. 4 (July 26, 2008): 523–32. http://dx.doi.org/10.1007/s11340-008-9159-8.

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Lalu, O., R. Darmon, and T. Lennon. "Spalling of high strength concrete in fire." IOP Conference Series: Materials Science and Engineering 1138, no. 1 (April 1, 2021): 012027. http://dx.doi.org/10.1088/1757-899x/1138/1/012027.

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Moccia, Francesco, Miguel Fernández Ruiz, and Aurelio Muttoni. "Spalling of concrete cover induced by reinforcement." Engineering Structures 237 (June 2021): 112188. http://dx.doi.org/10.1016/j.engstruct.2021.112188.

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Gao, Song, and Li Dai. "Study on the Anti-Spalling Performance of Concrete Pavement in Cold Area." Advanced Materials Research 243-249 (May 2011): 4297–301. http://dx.doi.org/10.4028/www.scientific.net/amr.243-249.4297.

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In accordance with the spalling of concrete pavement in cold area, this paper puts forward a concrete proportion after making plenty of experiments, which is carried out by adding flyash, silicon powder, air entraining and water reducing admixture with different contents and proportions to normal concrete, using flexure strength, compression strength, impermeability and frost resistance as evaluating indicators. The concrete proportion reaches high flexure strength and compression strength, good impermeability and frost resistance. According to the experimental results and economic analysis, it is shown that the concrete proportion can effectively reduce spalling of concrete pavement. Therefore, it has good use value and it is promising with a good prospect of application.

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Mussa, Mohamed H., Noor Azim Mohd Radzi, Roszilah Hamid, and Azrul A. Mutalib. "Fire Resistance of High-Volume Fly Ash RC Slab Inclusion with Nano-Silica." Materials 14, no. 12 (June 15, 2021): 3311. http://dx.doi.org/10.3390/ma14123311.

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The study aims to investigate the fire performance of reinforced concrete (RC) slab fabricated from high volume fly ash inclusion with nano-silica (HVFANS) under ISO 834 load curve. The HVFANS concrete slab with dimensions of 1850 mm × 1700 mm × 200 mm was tested via an electrical furnace under an exposing temperature of 1100 °C for 120 min. The slab behaviour was evaluated in terms of residual compressive strength, temperature distribution along its thickness, spalling, and cracks. The results revealed that the slab was capable of maintaining 62.19% of its original compressive strength at room temperature after exposure to the above temperature. Moreover, the distribution of temperature revealed that the temperature of concrete cover and bottom reinforcement was less than 300 °C with a maximum spalling depth of 11 mm within the temperature range of 680 to 840 °C. Furthermore, the thermal conductivity index (K) of the HVFANS concrete was determined, and results indicated that thermal conductivity equalled 0.35 W/mK which is considered low, as compared with other concretes tested in current and previous studies.

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Galek, Artur, Harald Moser, Thomas Ring, Matthias Zeiml, Josef Eberhardsteiner, and Roman Lackner. "Mechanical and Transport Properties of Concrete at High Temperatures." Applied Mechanics and Materials 24-25 (June 2010): 1–11. http://dx.doi.org/10.4028/www.scientific.net/amm.24-25.1.

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When concrete structures are subjected to fire loading, temperature-dependent degradation of the material properties as well as spalling of near-surface concrete layers has a considerable effect on the load-carrying capacity and, hence, the safety of these structures. Spalling is caused by interacting thermo-hydro-chemo-mechanical processes with both mechanical and transport properties playing an important role. Within experimental research activities at the IMWS, these properties are subject of investigation, i.e., (i) the strain behavior of concrete under combined thermal and mechanical loading and (ii) the permeability increase of temperature-loaded concrete and cement paste.

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Journal articles on the topic 'Concrete spalling'

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