EVALUATION OF THERMAL PROPERTIES OF DIFFERENT CEMENT BRANDS IN SOUTHERN NIGERIA
- GENERAL INTRODUCTION
- BACKGROUND TO THE STUDY
Cement is a fine grey or powder substance made by calcining lime and clay mixed with water to form mortar mixed with sand, gravel and water to make concrete.
Selection and utilization of suitable materials for any construction work during design and execution is pertinent. Failure of concrete structures is usually attributed to incorrect selection of material amongest other factores (McGinly and Choo, 1990).
Cement a mojar binging material in making concrete, influence the quality of the concrete so produced with it. Most local construction industries in southern Nigeria rely most often than not on their experience, availability and cost in selecting the brand of cement to be used in construction, at the expense of quality. Moreso,the quality information presently available in the bag of different brands of cement as given by the producers are not adequate to enable an assessment of the behavior of cement in a concrete mixed.
For instance, setting behavior of cement is not highlighted on the container of this cement. Recently poor quality cement has been implicated as one of the major causes of increment building collapse in Nigeria. Consequently, the standard organization to be used for different construction works and this had generated ripple among the stake holders in construction industries.
Therefore, research is the direction is not only timely but may serve as a basis for many contractors to select appropriate cement for their construction work. However, Yahayah (2009) carried out a similar work but he work did not consider many of the cement brand found in our study area.
Nigeria being a developing country consumes more cement, its infrastructural development. As at 2009, about 19.5 million tonnes of cement were consumed ---- with more than 60% imported (Frankli, 2009). In order to meet local demand, licenses are given to individual to import cement while local industries are given incentives to support local production. Presently, more than eight brand names of Portland cements are found in different locations in the country with about two of them are common in the southern region (Unicem Portland cement and Dangote Portland cement).
The quality of cement may differ from plant to plant due to changes in raw material properties, Klin temperatures as well as fineness upon grinding. These changes can significantly affects the concrete properties when different cements are used, for example, the tricalcium aluminates (CaзS), though the ability to predict shrinkage is based on compound composition may not be precise. The ultimate compressive strength and rate of strength development of concrete is strongly influenced by the chemical reactivity of Portland cement, varying hydration rates of the different cement compounds can help explain how the relative proportions of these compounds affects the rate of strength gained several other researcher have demonstrated the effect of cement content on the properties of concrete produced Gazatanga et al (1997).
The thrust of this study therefore is to carry out and evaluate the thermal properties of different cement brands in southern Nigeria with a view to making appropriate recommendations for the local construction industries that many not have the wherewithal to perform this. It could also be a basis for them to select appropriately the cement to be used for different construction works.
1.2 AIMS AND OBJECTIVES OF THE STUDY
- The aims and objectives of this research work are as follows:
- To determine the thermal properties of different cement brands.
- To implement accuracy of the brand has less coefficient of thermal conductivity.
- The temperature at which a given mixture of concrete increases and decreases.
- A brand of cement suitable for construction and building at a given seasonal change.
- To determine the strength and compatibility of different concrete mixtures.
- To determine adequate proportions of cement and sand mixture for building.
1.3 `SIGNIFICANCE OF THE STUDY
The significance of this research work are to study the thermal properties and conductivities and to investigate the effects of temperature on different cement brands which will enable user to identify a specific brand of cement for a specific work on a particular environment depending on the condition of the environment.
The important and outstanding significance is to identify a particular brand of cement with less strength of specific heat and thermal conductivity
1.4 SCOPE OF THE STUDY
The scope of the study will be a suite of phased tests that has been developed into a protocol of relatively simple tests to assess the thermal potential for incompatibility in a given brand of cements.
If the result of this test indicate possible problem, a more sophisticated set of test can then be applied to more firmly establish the risk of problems and possible remedial action.
The following is a list of components in the scope of this project;
- Conduct a literature review
- Develop guideline and tests for evaluation of thermal properties of cement
- Submit a final report documenting the work performed.
1.5 DEFINITION OF TERMS
Thermal: a column of rising air in the lower atmosphere created by uneven heating of earth’s surface.
Conductivity: the ability of a material to conduct electricity, heat, fluid or sound.
Cement: a powdered substance that develops strong adhesive properties when mixed with water.
Aggregate: a mass, assemblage or sum of particulars, something consisting of element s but considered as a whole OR A mass formed by the union of homogeneous particles.
Mineralogical: the branch of the study of the origin, composition and structure that studies minerals.
Surface: the up-side of a flat object such as a table or of a liquid.
Diffusivity: a coefficient of diffusion especially the amount of heat that passes through a given area in unit time.
Coefficient: a number, value of item that serves as a measure of some property or characteristic.
Expansion: the fractional change in unit length per unit length per unit temperature change.
Block: a hardened rectangular object of mud, clay used for building.
Shrinkage: the proportion by which something contract to become smaller.
Reinforcement: the state of reinforce.
Limestone: abundant rock of marine and fresh water sediments composed of calcite (CaCo)3 which occurs in both crystalline and amorphous.
Quartzite: a metamorphic rock consisting of interlocking grains of quarts.