2.0 REVIEW OF LITERATURE
2.1 GENERAL
Many Researchers have studied the effect of replacement of Portland cement by Metakaolin and also on fibre addition on the mechanical and durability properties of ordinary Portland cement concrete. The literature being reviewed is given under Review of literature of concrete containing pozzolanic materials such as Metakaolin. .
2.2 REVIEW OF LITERATURE OF CONCRETE CONTAINING POZZOLANIC MATERIALS SUCH AS SILICA FUME AND METAKAOLIN
Yogendran et al. (1987)19 made an attempt to modify the properties of concrete with respect to its strength and other properties by using silica fume and chemical admixtures. They concluded that optimum replacement of cement by silica fume for high strength is found to be
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De Angelis, and S.Pagaliolico (1998)43 in their investigation, super-plasticized mortars containing Metakaolin (MK) as 15% replacement of cement and with a water/binder ratio of 0.33 have been characterized with four commercially available MK samples have been studied and compared to silica fume. Three out of four Metakaolin samples showed improvement in compressive strength at early ages, when compared to SF, but at 90 days and later the difference is reduced. The difference in the compressive strength between the specimens with micro fillers and the control decreases after 28 days, because of a smaller slow down of the hydration rate in the control. This can be related to the fineness of the micro-filler in the specimens with Metakaolin. At 90 and 180 days Metakaolin and silica fume specimens gave similar strengths.
F.Curcio and B.A. De Angelis (1998)44 in their investigation, cement pastes containing Metakaolin have been studied with a co-axial cylinder rotational viscometer. They show a dilatent behavior that is strongly dependent on the water /binder ratio, on the level of cement 18 the total shrinkage of the MK concrete is constituted by autogenous shrinkage, the smaller part being drying shrinkage. Particularly at higher Metakaolin replacement levels, drying creep, basic creep and total creep were greatly
(Mazzassa – Lea's science). Calcium silicate hydrate is the fundamental result of lime-pozzolan response. Calcium aluminous hydrate, hydrated gehlenite, calcium carboaluminate, ettringite and calcium aluminous monosulfate are a percentage of alternate items that outcome from the lime-pozzolan response notwithstanding calcium silicate hydrate. (Admixtures for cement T.erdogan). The hydration between slica of pozzolans and calcium hydroxide are given by mathematical statement.
In this paper we have studied compressive strength of concrete by replacing natural aggregate with recycled aggregate by 25%, 50% and 75%.This mixture formed in the sample of cubes of dimension 150x150x150mm3.
Aitcin P.C, “Cements of yesterday and today Concrete of tomorrow”, Cement and Concrete Research, Vol. 30, (2000), pp 1349 - 1359.
Concrete and masonry products contain silica sand and rock containing silica. Since these products are primary materials for construction, construction workers may be easily exposed to respirable crystalline silica during activities such as the following:
Lightweight concrete plays a major part in the construction of large-scale structures around the world, typically in bridges and high-rise buildings. With an ever-improving industry and product lightweight concrete will continue to have a vast impact in the future.
Concrete is a composite material used widely in the construction industry. Concrete is basically a mixture of cement, water, aggregates and admixture (sometimes). Cement is a fine gray powder that consists of oxidizes calcium, silicon and aluminum. The aggregate used is normally gravel, crushed stone or sand. Admixture is a solid or liquid substance that gives a certain characteristics of the concrete. The cement reacts with water chemically and binds the aggregates together through a process called hydration during hardening or curing of concrete. It means that water helps in the hardening of the concrete while the cement bind the aggregate and also react with water to form a solid mass.
Through investigating the various properties of Cement/Concrete/Mortar, Glass, and Ceramics/Porcelain I have come to understand the chemical composition, type of bond, structure, and the daily use of each of the substances. Cement is composed of calcium which usually is acquired from limestone and silicon which is usually from sand, shale or clay (aluminosilicates). The structure of cement is in between the two extremes of an ionic and a covalent model. It is between an ionic oxide lattice and a tetrahedral covalent network. Cement when wet or when dry has both cohesive and adhesive properties. Concrete is created through the mixture of cement (filler), fine and coarse aggregate (binder), and water. With the characteristics of these materials, concrete’s type of bond attributes to its high thermal insulation properties and the strength of the material itself. Concrete is used for building materials and due to its thermal insulation properties as insulators. Mortar is a mixture of cementitious materials, water, and aggregate. For commercial use in buildings and constructions, it is useful by having water retentivity and its strength after stiffening and hardening. In addition, the content in the mortar of cement as well as air content affects the strength of the tensile bond between the mortar and the masonry. Due to the materials that compose mortar, it developed a chemical structure that is similar to its components. Also, in daily use, mortar is used for construction for buildings to attach segments together.
Cement is a finely ground compound of limestone and clay or marl (Chandigarh, 2001). It is used in hydraulic binding since it hardens and binds together aggregates and becomes waterproof thereafter. The most popular use of sand is in building and construction where it is used to bind sand and gravel to obtain concrete used in constructing houses, roads, water channels, among others. Yanbu Cement company produces different types of cement such as Portland cement types I, II, III and IV.
The length of time for which the concrete mixture remains plastic predominantly depends on the …………………………………………………
Fly ash is a by-product of coal from power stations. It helps to improve the durability of concrete. Through the observation under the SEM test, It can be noticed that the fly ash sample consists of almost regular spherical or cenospheres particles ranging 2 um to 14 um in diameter (Ismail et al., 2007). This is due to the fact that fly ash is produced by fusing small and light particles that remain suspended in the burning chamber but are captured afterwards by electrostatic filtration equipement (Rivera et al., 2013). The huge particle size of fly ash enables it to be ball mill again in order to reach a smaller particle size. Based on past research, the binding of OPC with fly ash increases the compressive strength due to the denser
The ratio of flexural strength to compressive strength of lightweight foamed concrete (LWFC) was in the range of 0.06-0.10 and this ratio was also found to reduce with increasing water-cement ratios and decreasing densities (Deijk, 1991). The splitting tensile strengths of LFC mixes were higher for mixes with sand than those with fly ash. This was attributed to the improved shear capacity between sand particles and the paste phase. (Jones and McCarthy, 2005)
Concrete is most widely used material for various applications in this world. India is second largest producer of concrete in world. As this is used in various applications its base properties which are obtained by preparing concrete with required raw materials must be enhanced by adding some other material to it. There comes the role of admixtures by which one can extract required property from concrete. There are various two basic classifications of admixtures. Chemical and Mineral admixture. There are various types of mineral admixtures. Most of mineral admixtures are by-products available from some production industry. Silica fume is a mineral admixture which is obtained as by-product of silicon industry is a costliest material but is very desirable material for normal concretes. Footprint of Nanotechnology which is defined as science of controlling the properties at nanometer scale which can make revolutionary changes in bulk material properties [23] in construction field has great impact in improving the properties of concrete . There are many types of nano-materials like nano-silica, nano-alumina, carbon tubes etc.. This paper describes how the properties of concrete are enhanced by adding nano-silica to it and compares with concrete containing microsilica. Both nano-silica and micro-silica are siliceous admixtures having higher contents of amorphous silica but nano-silica is the one having 1/10th size of silica-fume which is major advantage for nano-silica to enhance different properties of concrete to larger extent than microsilica.
Previous study about the Ordinary Portland Cement (OPC), High Performance Concrete (HPC), And Ultra High Performance Concrete(UHPC) there are different result about the penetration of chloride ions to the specimen. This because, the reinforced concrete are exposed to harsh environment yet often expected to last with little or no maintenance for a long periods of time. The lacking maintenance of the concrete may cause this problem become worse and the concrete may not suitable to used.
Laboratory experiments have shown that cement degrades would occur once exposed to such CO2 rich environments [10]-[12], [16], [22], [72]-[74], [30]. It tends to degrade rapidly once exposed to such acid gas by reacting with Ca(OH)2 and C-S-H. The mechanism of degradation process starts when CO2 gas is exposed in a wet environment, it will...
studied the advantages of using a mortar-based mix design methodology for C-SCC. Many mortars and colored SCC were prepared including different pigments shape and fineness. Synthetic pigments are extensively used as color agents in cement based materials (Ordinary ‘‘grey” Portland cement (G) or white Portland cement), their requirements are included in many sources (Bower et al, 1964 and Buehrer et al, 1987) [28-29]. Three iron oxides yellow (y), red (r), black (b), carbon black (c) and two copper phthalocyanines blue (phg) and green (phg) were used. Some pigments can strongly increase air incorporation in fresh concrete, as in the case of the cupric phthalocyanines (Barragan B.E. et al, 2008) [30]. Mortar tests are also effective to detect this fact. It can be seen a significant increase in air content appears when phthalocyanine pigments were used; as a consequence notable reductions in strength must be expected