Academic literature on the topic 'V-funnel'

Self-compacting concrete (SCC) is a type of concrete, which flows under the sole influence of gravity up to leveling, air out and consolidates itself without any external compaction energy. It was a response to the lack of qualified skilled workers at the construction sites and a solution for the accomplishment of durable concrete structures. Self-compactability of a concrete mix is widely affected by the characteristics of ingredients and their proportions. Thus, it becomes necessary to develop a successful procedure for mix proportioning of SCC. The heuristic nature of the early mix proportioning methods motivated researchers to carry out extensive research on the rheological properties of SCC that has significantly improved the proportioning of SCC mixes. A rigorous proportioning method for SCC based on sound physical principles was proposed. However, such a method produces a bewildering array of mixes that reach the target plastic viscosity but does not give any practical guidelines on how to choose the most appropriate mix and does not explicitly impose compressive strength as a design criterion. These shortcomings were overcome in this work by developing a new mix proportioning method. Indeed, practical guidelines in the form of design charts were provided for choosing the mix proportions that achieve a target plastic viscosity in the range 3 to 15Pa s (the lower limit varies with target cube compressive strength) and a target cube compressive strength in the range 30 to 80MPa. To verify the proposed mix design method, an experimental validation was performed on a series of SCC mixes in both the fresh and hardened states. Three sets of SCC mixes were prepared jointly with other two PhD students (Abo Dhaheer, 2016; Al-Rubaye, 2016). These mixes are designated A, B, and C for the low, medium and high paste to solids ratios, respectively. (Note that mixes designated A and C were contributed by the other two named PhD students). Tests on these mixes conclusively proved the validity of the mix design approach in the sense that all the mixes met the self-compactability criteria and achieved the desired target plastic viscosity and cube compressive strength. vii Although SCC has passed from the research phase into the real application, the differences in its composition (i.e. higher paste volume and lower coarse aggregate volume) from normal vibrated concrete (NVC) raise concerns among researchers about its fracture behaviour. Thus, an experimental study has been carried out to investigate in detail the role of several composition parameters of SCC mixes on their fracture behaviour differing by the coarse aggregate volume, paste to solids ratio (p/s) and water to cementitious material (w/cm) ratio. The specific fracture energy and the tension-softening diagram of a concrete mix are the most critical parameters that describe its fracture behaviour as they form a basis for the evaluation of the load carrying capacity of cracked concrete. First, the size-dependent fracture energy (Gf) has been determined using the RILEM work-of-fracture test on three point bend specimens of a single size, half of which contained a shallow starter notch (notch to depth ratio=0.1), while the other half contained a deep notch (notch to depth ratio=0.6). Then the specific size-independent fracture energy (GF) was calculated using the simplified boundary effect formalism in which a bilinear diagram approximates the variation in the fracture energy along the unbroken specimen ligament. Finally, the bilinear approximation of the tension softening diagram corresponding to GF has been obtained using the non-linear hinge model. Predicting the flow behaviour in the formwork and linking the required rheological parameters to flow tests conducted on the site will help to optimise the casting process. A Lagrangian particle-based method, the smooth particle hydrodynamics (SPH) is used to model the flow of SCC mixes in the V-funnel. An incompressible SPH method was employed to simulate the flow of such a non-Newtonian fluid whose behaviour is best described by a Bingham-type model, in which the kink in the shear stress versus shear strain rate diagram is first appropriately smoothed out. The basic equations solved in the SPH are the incompressible mass conservation and momentum equations. The simulation of the SCC mixes emphasised the distribution of larger aggregates particles of different sizes throughout the flow in the 3-dimensional V-funnel configuration. The capabilities of this methodology were validated by comparing the simulation results with the V-funnel tests carried out in the laboratory.

Fresh properties of mortars are important factors in altering the performance of self compacting concrete (SCC). Measurement of the rheological properties of the fine mortar part of concrete is generally used in the mix design of SCC. It can be stated that SCC rheology can be optimized if the fine mortar part of concrete is designed properly. However, measurement of the rheological properties is often impractical due to the need for complex equipment. Therefore, more practical methods of assessing mortar workability are often preferred. In this study, four mineral admixtures, three superplasticizers (SP) and two viscosity modifying admixtures (VMA) were used to prepare self compacting mortar (SCM). The mineral admixtures included fly-ash, brick powder, limestone powder, and kaolinite. Two of the SPs were polycarboxylate based and another one was melamine formaldehyde based. One of the viscosity modifying admixtures was based on an aqueous dispersion of microscopic silica and the other one was based on high molecular weight hydroxylated polymer. Within the scope of the experimental program, 43 mixes of SCM were prepared from different materials with keeping the amount of mixing water constant. Workability of the fresh mortar were determined using V - funnel and slump flow tests. The setting time of the mortars, were also determined. The hardened properties that were determined included the ultrasonic pulse velocity (UPV) and the strength which was determined at 7, 28, and 56 days. It was concluded that among the mineral admixtures used, only fly-ash and limestone powder increased the workability of the mixes. The two polycarboxylate based SPs yield approximately the same workability and the melamine formaldehyde based SP was not as effective as the other two.

Věra Sušická - Diplomová práce 2012 Anglický překlad The final work is concerned with the remanis of dwelling in the context of Funnel Beaker culture. It is divided into five basic regions. In general these regions are consisting of south Scandinavia, the Netherlands, Germany, Poland, Bohemia, Lower Austria and west Ukraine. 76 localities were obtained from all these regions. There was proof of more then 160 dwellings (Underground/dig houses, post hole houses). Particular types of dwellings and their functional characteristics were described typologically and chronologically. The finds were scrutinized, especially the czech ones. This work also further discusses the issues of the survival process of mentioned dwellings and the ways of evaluation and research. Klíčová slova: Funnel Beaker Culture -Central European kontext - dwelling structure - post hole houses - dig houses Obsah: Text - 117 str. (47 poznámek pod čarou), literatura a prameny - 18 str., obrazové přílohy - 19 obr., tabulky - 44 str., mapy - 5 listů (celkem: 193 listů ve formátu A3, 4 listy ve formátu A4).

The polycultural settlement area in Libeznice (Prague-East district) represents a relatively large complex of many different settlement structures, mostly of Funnel Beaker culture and Hallstat period, as well as three Unetice culture tombs and a skeleton burial probably of La-Téne period. An archaeological excavation, which was caused by the construction of a ring road, took place in the years 2008 and 2009. During the works several dozens of settlement structures of Funnel Beaker culture were uncovered - a large open settlement with a number of long houses and other structures. This thesis follows my bachelor thesis, where a chosen group of sixteen structures is analysed. In this thesis a remaining group of nineteen settlement structures is dealt with and published and its ceramic artefacts and also chipped stone industry, polished stone industry and bone industry are analysed in detail. On the basis of its morphological features coincident with previous results was this settlement dated to the younger period of Funnel Beaker culture, i.e. to the salzmünde phase, followed by a small collection of ceramics of Boleráz phase (Baden culture). Middle Eneolithic period - Funnel Beaker culture - Salzmünde phase - habitation area - Bohemia