Optimization of the various strengths of concrete made from two different types of coarse aggregates using Scheffe’s model

Abstract

This research work on the Optimization of the Various Strengths of Concrete Made from Two Different Types of Coarse Aggregates using scheffe’s model. The coarse aggregates (crushed and uncrushed) was obtained from Nkalagu, Ebonyi State. Cement was bought from Kenyatta market, sharp river sand was collected from Nyama River here in Enugu State and water used was gotten from Enugu state water corporation. The practical tests were conducted at Enugu State University of Science and Technology (ESUT) Laboratory, Enugu. Tests that were carried out were series of tests, specific gravity, casting and crushing of the cubes and compressive strength tests were carried out. Natural sand with fineness modulus of 2.27 was used as fine aggregate. Ordinary Portland cement was used as binding material. Mix proportions 1:1:2 with crushed and uncrushed aggregate types were used in the research. The water/cement ratio adopted for the study was 0.59 throughout the experiment. The target mean strength at 28days was 25N/mm2. Twelve concrete cubes (150mm x 150mm x 150mm) were cast for each coarse aggregate type of which three were crushed at each maturing age namely 8, 14, 21, and 28 days from each mix, 12 cubes were cast for each of the two types of coarse aggregate, making a total number of 24 cubes. The concrete cubes are to be casted in laboratory and tested in hydraulic compression testing machine.