High Silica Performance Concrete, E & Fn Spon : New York

A specific subset of recycled aggregates is recycled concrete aggregates (RCA) where the masonry content is limited to not more than five per cent. The performance characteristics of RCA are better than RA and consequently there are fewer restrictions on the use of RCA in concrete (BS 8500-2)

This is the most recent type of concrete formwork. It’s an emerging tech for RCC construction as well as architectural design work. This materials’ flexibility creates the ability to make concrete of any shape.

Most people think concrete is an impenetrable solid. But in actually, concrete is a porous material with many capillaries and voids throughout the surface. Although concrete is strong in compressive strength, it is weak in tensile stength and elasticity. Concrete can tolerate heavy loads, but it is susceptible to damage which causes it to break apart over time.

Aggregate is one of the basic constituents of concrete. Its quality is of considerable importance because about three-quarter of the volume of concrete is occupied by aggregates. One of the physical properties of aggregate that influence the property of concrete is the grading of aggregate. The grading of aggregate defines the proportions of particles of different size in the aggregate. The grading of fine (size < 5 mm) and coarse (size > 5 mm) aggregates are generally required to be within the limits specified in BS 882: 1992.

For those used to concreting on dry condition, concreting under water presents various challenges. Transporting, compacting, quality control, finishing and accuracy must all be carried out successfully in this different, and often difficult, environmental conditions. There are, however, many common aspects, chief of which is that air is not required for the setting and hardening of concrete – it sets and hardens just as well, and often even better, under water. Moreover, it must be fluid enough to flow into position and be self-compacting as conventional vibration is not practicable under water. During transporting and placing, conventional concrete and water must be kept apart and, when they inevitably do come into contact, rapid interface flow must be minimized or cement may be washed out to form a weak layer. Washout can be avoided by the use of an admixture to make the concrete non-dispersible but this comes at a cost and contractors unwilling to pay the additional expense involved often adhere to the more traditional methods of placing under water.

In order to produce High Performance Concrete, cement which containing as little C3A as possible should be used during manufacture process. This is because the lower amount of C3A, the easier to control the rheology properties on cement. Other than that, the cement-super plasticizer compatibility problems can also be reduced. Finally from strength point of view, this cement should be finally ground and contain an appropriate amount of C3S.

Yield line theory is a productive method for deciding the breakdown heap of strengthened concrete slabs, and it pre-dates limit examination. The term 'yield line ' (in Danish: 'brudlinie ', truly signifying 'line of crack ') was authored in 1921 by Ingerslev to depict lines in the slabs along which the twisting minute is steady [1]. In 1931 K W

ABSTRACT Self compacting concrete with suitable chemical admixtures like Super Plasticizer and viscosity modifying agent can be cured, alternatively by addition of an internal curing agent instead of using large quantities of water. Steel fibers on the other hand have been used in cement and concrete composites for more than four decades, most of the steel fibers were introduced in the market prior to 1980. This is in sharp contrast to the continuous progress and development in the cement matrix itself. The proposed aim of the experiment is to examine the behavior of self compacting self-cured concrete by changing the steel fiber content. The mix incorporated 40 % replacement of cement with fly ash. The compressive strength and flexural strength of concrete were compared with conventional concrete by adding 0.5%, 1% and 1.5% of steel fibers and a notable accession of 79% in flexural strength was observed without compromising with the compressive strength.

The report will mainly focus on the differences between reinforced, prestressed and partially stressed concrete. These concrete reinforcing methods differ in the period they have been used. Reinforced concrete was developed by a nursery owner in Paris in 1867, Joseph Monier, applying it to practical use for the first time (Salmon & Wang, 2007). Prestressed concrete’s discovery dates back to the late 1800’s. Freyssinet was one of the first engineers who used this method and realised that, for this method, high quality concrete with very high tensile steel wires, stressed as high as possible was needed (Chris Burgoyne, 2005).

The objective of the hardened concrete test was to determine the compressive and indirect tensile strength. On the other hand, this experiment was also used to examine the effect of curing condition on strength of concrete, the influence of specimen shape on compressive strength, the effect of compaction on compressive strength and this experiment was also to examine the effect of increasing water to cement ratio on compressive and in direct tensile strengths of concrete.

Over the past quarter century, many of both the experimental and analytical studies have increased dramatically on the monotonic behavior of FRP-confined concrete columns, and as a result, many axial stress-strain models have been proposed; however, most of them have focused largely on FRP-confined plain concrete cylinders numerous people tested (e.g., Mirmiran and Shahawy 1997; Mirmiran et al.1998; Xiao and Wu 2000; Lam and Teng 2002, 2003; Berthet et al.2005; Almusallam 2007; Benzaid et al.2008; Eid and Paultre 2007, 2008; Teng et al.2009; Smith et al. 2010; Cui et al.2010). A certain number of these researches have included non-circular unreinforced (plain) columns (e.g., Rochette and Labossiere 2000; Ilki and Kumbasar 2002; Youssef 2003; Rousakis et al.2007; Youssef et al. 2007; Benzaid et al.2008; Wu and Wei 2010; Wu and Zhou 2010; Benzaid and Mesbah 2013). Owing to the limited progress of the experimental investigations carried out on FRP-confined non-circular reinforced concrete columns (RC) tested under cyclic axial compression loading, a well-defined study indicates that a few essential gaps need more further research. As a result, the current study aims to consider the most significant issues, namely, the influence of 1) cross-sectional aspect ratio, 2) internal hoop or longitudinal steel reinforcement ratio, and 3) cyclic or monotonic compression loading pattern. These issues which form the basis of the experimental program on CFRP-confined rectangular reinforced

Concrete is known as a construction material which is widely used throughout the entire world. According to the research, concrete contains Portland cement and it is an essential element to concrete (Naik and Moriconi, 2010). This essential element is capable of releasing carbon dioxide significantly. As carbon dioxide is known to be a green house gas, hence it can be said that this type of concrete is damaging the environment. In order to save the environment a new technology is made by which eco – friendly concrete can be made. Such concretes are made of the concrete wastes that are known to be eco – friendly; therefore, the concrete is also eco – friendly. This type of concrete is also known as green

This experiment was therefore aimed at determining the ultimate compressive strength of different concrete samples after 14 days. Additionally, other properties of the concrete such as modulus of elasticity and Poisson ratio were also determined.

The macroscopic material behavior of concrete is influenced by the geometry, spatial distribution and material properties of individual material constituents and their mutual interactions. Therefore, it is essential to study the influence of each material constituent in order to estimate the residual strength of the structural components. Thus, failure of concrete is a complex phenomenon due to its multiscale and multiphase nature. When the normal stress in a material reaches its tensile strength, the inhomogeneities in concrete promote the formation of an inelastic zone ahead of an existing crack termed as the fracture process zone (FPZ). The FPZ is dominated by various complicated mechanisms such as crack shielding, crack deflection, aggregate bridging and microcracking around the crack tip and exhibits a post-peak softening behavior under tensile loading. It therefore becomes necessary to include these effects for predicting reasonably well the residual strength of existing cracked and damaged structures.

In chapter 2, literatures of concrete modelling have been reviewed. The scope of this chapter is to describe the finite element software" SOFISTIK" to simulate the nonlinear behavior of the foam balls lightweight concrete. The results from this numerical technique are presented and validated with the experimental results obtained from the laboratory tests. The results obtained from these experimental and numerical investigations are taken to predict the nonlinear behavior of 150x150x150 mm FBLWC cube. The damage plasticity concrete concept is used to model the foam balls lightweight concrete cube in the SOFISTIK. Meanwhile, a spring elements are considered to reproduce the nonlinear FBLWC behavior. They are taken into account to develop the F.E.M. structural analysis to obtain stress-strain responses.