The comparison of the compressive strength of concrete made with crushed stone Essay

Concrete is the most widely used composite material today. Concrete has been in use as a major building material ever since its inception world over, last three four decades have seen construction of innumerable reinforced concrete structures with compressive strength of concrete in the range of 60 100N/m2. Concrete is a composite material composed of coarse aggregate (crushed stone or gravel), fine aggregate (river sand or stone dust), cement, water and additional admixtures if necessary. Concrete is one of the versatile and widely used building materials in the world of construction industry. The properties of high strength concrete are influenced by the properties of the aggregate and water/cement ratio.
Plain concrete is made by mixing cement, fine aggregate, coarse aggregate, water and admixture (Wang and Salmon, 1998). According to the compressive strength, concrete can be classified as follows concrete having cube compressive strength at 28 days up to 15N/m2 is low grade concrete, between 16 to 50N/m2 is medium grade, between 51 to 100N/m2 is high grade and beyond 100N/m2 is ultra- high strength concrete (Kishore, 1995). In addition the strength of concrete mainly depends on amount of water used, aggregate gradation, and aggregate size and shape, cement quality, mixing time, mixing ratios, curing etc. (Kabir, 2006). However, facts reveals that fine and coarse aggregates makes up 70% and above by volume of all concrete mix or production.
The coarse aggregate to be used for the production of concrete is crushed stone either crushed in the quarry (by a more efficient equipment and automation procedure) or manually crushed (by means of Explosives, Fire, Chemical and Hammer).
Crushed stone is a form of coarse aggregate which is in high demand for the production of concrete for almost all construction purposes today. Crushed stone is one of the most accessible natural resources, and is a major basic raw material used as coarse aggregate in concrete mix in the construction industry. Crushed stone is a high volume, low value construction material used as coarse aggregate because of its remarkable strength, which in turn improves the strength of the concrete produced for construction purposes.The construction industries in the developing world seeks the use of alternative means of crushed stone production, which caner place the demand for crushed stone from the quarry, thereby reducing environmental load on crushed stone from the quarry, reduction of production and transportation cost as well as augmenting the quality of concrete (Lohan et al 2012). Compressive strength is the criterion for the determination of the quality of concrete (Troxel et al 1968) and as such it becomes necessary that for a concrete to be used, its compressive strength has to be determined. In this research work, we look forward to comparing the compressive strength of concrete made with crushed stone manually processed and that made from quarry as coarse aggregate in the production of concrete. This research focuses on quantitative analysis of the strength of concrete produced from other means the crushed stone has be obtained compared to