Thesis Self Compacting Concrete

Aggregate bridging is one mechanism that has been identified to explain the “self-support” of SCC that occurs soon after SCC material is at rest (and well before the point traditionally defined as “set”). It is thought that as the material fills its form the aggregate will line up and touch each other to form a skeleton in the fresh concrete. As the gelation and hydration processes occur, this bridging will get stronger and will lead to a drop in formwork pressure. This mechanism continues to be studied, but there have been results to show the affect of varying coarse aggregate fractions in SCC mixtures. It has been shown that for mixtures of similar proportions of binder but varying coarse aggregate to fine aggregate ratios that the mixtures with greater coarse aggregate contents will exhibit reduced initial pressure and a faster pressure drop.

Self Compacting Concrete Phd Thesis

  (2013)Corrosion inhibition in self-compacting concrete. PhD thesis, University of Nottingham.

Self-compacting high performance concrete, ed Okamura, H., 1999.

Concrete is a composite material which consists essentially of (a) fluid phase called the cement paste and (b) solid phase of aggregates with fixed gravel/sand ratio. Self-Compacting Concrete (SCC) requires both high fluidity to flow under the effect of gravity alone and a good resistance to segregation. Since, controlling the flow properties of cement paste can lead to the control of self-compacting abilities at full concrete scale (Saak ., 2001; El Barrak ., 2009), it is necessary to understand the influence of each constituent on the flow behavior at paste scale. Many researchers have studied the influence of constituents on the flow properties of cementitious mixtures (paste, mortar and concrete) using statistical models (Violeta and Yachko, 2005). These approaches make it possible to highlight dominant parameters and to optimize the mixture formulation. When mixtures are optimized on quantitative basis, depending on the objective of the optimization, construction productivity could be improved, durability increased, and both material and construction costs reduced (Yeh, 2007). A multi-objective optimization of cementitious blends of mineral admixtures was studied to achieve an optimal mixture concrete proportioning (Gesoğlu ., 2009), which means that use of multi-scales optimization avoid an extensive series of tests. This leads to reduction of the costs in product development.

Self Compacting Concrete Phd Thesis

The self-compacting properties of the concrete depend necessarily on those of the cement paste that is why the study carried out on formulations is based primarily on the paste and its different components. The method used on materials from the Building Materials Laboratory (L.M.D.C - INSA-UPS, Toulouse, France) gave very satisfactory results, and it was then applied to Algerian local materials in order to obtain a self compacting cement paste formulation. The experiments were carried out using simple equipments which can be afforded by laboratories of moderate budget.

12. B. Birch, “Formwork Pressure of Self Consolidating Concrete,” MS thesis, University of Illinois at Urbana-Champaign, 2007.
1. Y. Vanhove, C. Djelal, “Formwork Pressures with Self-Compacting Concrete,” Concrete, June 2002, pp22-23.

Design and testing of self-compacting concrete - UCL Discovery

From a concrete technology point of view, those findings can be explained by the adsorption of the free water on a larger total surface area of a finer grading, thus leaving less water available for the lubrication of the cement paste itself. The recent findings have also indicated that varying the properties (flakiness) of coarser crushed sand fractions (0.125/2 mm and 2/4 mm) has much less relative impact on fresh concrete properties, and that the other fine particle (≤ 0.125 mm) characteristics, such as shape, surface texture and mineralogy, could have a similar effect as grading (specific surface).

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Self-Compacting Concrete | Creep (Deformation) | Concrete

The current trend in the concrete construction industry is an attempt to increase the market share of self-compacting concrete. This is a special type of very flowable concrete that was developed two decades ago in Japan and is special due to its ability to compact and level itself into a mold without any external vibration.

Formwork Pressure - Self-Consolidating Concrete

with Self-Compacting Concrete ..

The superplasticizer used in this study is ‘Viscocrete 20 HE’ provided by SIKA-Algeria. It is a no chlorinated product containing acrylic copolymer in liquid form and containing 40% of dry extract with a density of 1,085 kg m-3 and a pH of 4,5. It can be shown from several studies (Youjun ., 2002; Naadia ., 2004) that it is possible to prepare self-compacting concretes without using viscosity agent to remain in the context of local materials promotion, so this parameter will not be integrated in the preparation of the cement pastes.