CHAPTER ONE
INTRODUCTION
vii.    Background to the study
Various blends of cement utilized in construction are portrayed by their physical properties. Some key parameters control the nature and quality of cement. The physical properties of good cement are based on; Fineness of cement, Soundness, Consistency, Strength, Setting  time, Heat of hydration, Loss of ignition, Bulk density, Specific gravity (Relative density). In addition, cement has a very high cost in many developing countries like Nigeria and its usage cannot be sustained. The need for moderate structure materials in giving satisfactory lodging to people of the world has turned into the real worry of researchers.The expense of traditional structure materials keep on expanding as most of the populace keeps on falling beneath the destitution line. This consequently requires the look for elective neighborhood materials as aggregate or fractional swap for concrete (Adesanya and Raheem, 2009; Akinwumi and Aidomojie, 2015; Raheem &Adedokun 2017). The research has led to the discovery of the potentials of using industrial by-products and agricultural wastes as replacement of some cement materials.Agricultural and industrial wastes possess pozzolanic properties used in cement replacement.The  application  of  agro  and  industrial  wastes  in  the  production  of  cement  is  an environmentally friendly  method  of disposal  of large  amounts  of substances that  would have constituted pollution to land, water and air. The agricultural and industrial wastes that possessed pozzolanic characteristics and which had been studied  and applied  as partial  replacements for cement are Rice husk ash [6-9], Corn cob ash [4, 10-12], Waste burnt clay [13-14], Hair fibre [15] and Saw dust ash [16-17]. The saw dust ash (SDA) which has been proven to be a pozzolanic material was used as a partial substitution for OPC in this study. Many researchers have argued that concrete is one of the major materials used for radiation protection in facilities. The radiation protection feature of concrete depends on its components. Cement production is one of the important sources of carbon dioxide emission to the atmosphere. CO2, which is a greenhouse gas, contributes about 65% of global warming (Vijayakumar, 2013; Raheem &Adedokun 2017). The high energy demand as well as the emission of carbon dioxide, which caused global warming and depletion of limestone deposits are the major challenges associated with cement production.
In the recent years, there is great interest in replacing a long time used materials in concrete structure by new materials to produce cheaper, harder and durable concrete.Abdelrahman& El-Awney (2015).The raw materials for cement production are limestone (calcium), sand or clay (silicon), bauxite (aluminum) and iron ore, and may include shells, chalk, marl, shale, clay, blast furnace slag, slate. Chemical analysis of cement raw materials provides insight into the chemical properties of cement.
Corn, also known as maize, is one of the most successful cereal grasses of all time. It has been under human cultivation for over 10,000 years and has spread itself into every niche of commercial agriculture (Adesanya, & Raheem (2009). Maize crop started as a subsistence crop in Nigeria and has gradually risen to a commercial crop on which many agro-based industries depend on as raw materials (Iken, and Amusa, 2014).Corn stalk is a waste product obtained from maize plant, which is the major cereal crop produced in sub-Saharan Africa.Therefore, this research investigated the use of Corn stalk as a partial replacement for ordinary Portland cement in the production of concrete cubes. It includes the determination of the oxide,composition of the CSA, evaluation of the compressive strength, density, water absorption,crushing strength of the concrete and the abrasive resistance of the concrete cubes.
viii.    Problem statement
A major challenge in the constructions in the world today is access to good and quality cements with right proportions of its physical properties.The high price of good cement with balance property ratio has made it difficult for people to acquire it, hereby leading to usage of poor quality cement which later affect the construction.This study examined the physical properties of ordinary cements alongside blended cornstalk ash and how it improved the physical properties without unnecessary increase in the cost for effective and standard construction.