ABSTRACT
The current extensive use of low quality aggregate in Nigerian road for engineering applications is of concern because they appear to be a level of ignorance surrounding their existing properties and implications. This project was conceived for the purpose of comparing the crushed aggregate and one sample each was obtained from different locations and transported to ministry of works laboratory Enugu, Enugu State. These aggregate samples were tested. It also revealed that the standard strength for Abrasion is between 20 – 30 percent comparison were made between the results, precautions, procedures and observations. And this coarse aggregate should be tested and analyzed before using in any constructional purposes to ensure durability of engineering products. The highest and lowest compressive strength was obtained in the concrete specimens prepared with steel slag and calcareous limestone aggregates, respectively. Similarly, the split tensile strength of steel slag aggregate concrete was the highest, followed by that of dolomitic and quartzitic limestone aggregate concretes. The lowest split tensile strength was noted in the calcareous limestone aggregate concrete. The type of coarse aggregate also influences the modulus of elasticity of concrete. Weaker aggregates tend to produce a more ductile concrete than stronger aggregates do.
CHAPTER ONE
1.0 INTRODUCTION
The basic thing in investigation into the quality of aggregate in road construction is that aggregates serves as reinforcement to add strength to the overall composite material. Due to the relatively high hydraulic conductivity value as compared to most soils, aggregates are widely used in drainage application such as foundation and French drains, septic drain fields, retaining wall drains and road side edge drains. Also the quality of aggregates helps to prevent differential setting under the road that binds with more expensive asphalt. Furthermore, aggregates feature at all levels of road construction up to the surface which includes aggregates resistant to polishing, ensuring skid resistance. The quality plan or system should cover all quality aspect of source material handling aggregate processing, stockpiling and transportation including methods and frequency of sampling and testing to be used, and should also identify key responsibilities.
