INTRODUCTION

1.1  BACKGROUND TO THE STUDY

Concrete is a versatile construction material. According to Hasan and Kabir (2011), it is readily available, relatively cheap, flexible to handle and it gives shape and any desired form. The compressive strength is the most critical property that gives a very good overall idea of the quality of concrete, the tensile strength being negligible in comparison. In the broad sense, concrete is made of a cementitious material (cement, lime, pozolans etc., or any combination of these), aggregates (fine and/or coarse) and water. There may be some additives and/or admixtures added to the basic constituents to vary the properties of the concrete when it is green or hardened. Many researchers (Yeh, 2006; Jankovic, 2011) have carried out works to predict the strength of concrete at any given age using some developed models. They are many factors that affect the rate at which strength develops in concrete after mixing (Elaty, 2013). Among these factors are the richness of the mix, character and grading of the aggregate, the water content of the mix and the curing conditions (El-Nemri, 2011; Bruce et all., 2012). The porosity of concrete, changes with the degree of cement hydration (Jankovic et al., 2012). The degree of cement hydration which is a function of water to cement (w/c) ratio has a direct effect on the porosity and consequently on the strength. As stated earlier, the richness of the mix is one of the factors that affect the rate of strength development in concrete. The richness of a concrete mix is a direct function of the quantity and quality of the cementitious material.

1.2 AIMS AND OBJECTIVE OF STUDY

The major objective of this study is to examine the strength development in concrete using different cement particularly in Nigeria. This project work unveils the very facts behind concrete strength in the construction industry.  

1.3  SIGNIFICANCE OF STUDY

In the Nigerian construction industry, the most commonly used cementitious material is the Ordinary Portland Cement (OPC). Of recent there has been a serious controversy as to whether the brands of OPC used in the country can attain adequate strength. In fact the Standard Organisation of Nigeria (SON) even attributes the incidences of building collapse in the country to this assumption. Concrete gains strength with increase in age, and this is regardless of the grade, but it is important to know how much of this strength is gained at any particular age between the ages of 1 to 28 days. It is also important to know whether the cement brands produced and used in Nigeria develop adequate strength when used to produce concrete to meet the desired strength. Also it is needful to know the rate of strength development to be able to decide on the time to strike the formwork during construction.