An investigation of the impact of fine aggregate type proportioning on compressive strength of cement concrete

Abstract

Several reinforced concrete buildings have collapsed in Uganda and one of the major causes is poor materials and workmanship. Substandard materials, especially, low-quality cement concrete as construction materials lead to the failure of structures in Uganda before design life, and some structures fail during the construction phase. The objective of this study was to investigate the impact of fine aggregate type proportioning on the compressive strength of cement concrete. Five fine aggregate sources were sampled from central districts of Uganda and taken to the laboratory, where 792 cement concrete cubes of 20MPa, 25MPa, and 30MPa from different combinations were made from lake sand and plaster sand for both good and poor-quality sand. Different laboratory tests were conducted to find the different properties of concrete ingredients and a compressive strength test was conducted using a UTM machine. Experimental data was analyzed to determine the effects of the volume combinations of fine aggregate types on the cement concrete compressive strength, and the combination of 70-80% lake sand: and 20-30% plaster sand achieved more value of average compressive strength than other combinations. Fine Aggregate combinations 100:0, 50:50, and 0:100 (lake sand to plaster sand) showed relatively low impact on the compressive strengths at any age, which answered why there’s a need to blend different types of sand. Using the one-way Analysis of Variance (ANOVA analysis), the relationship between the changes in average compressive strength values and aggregate volume fractions was analyzed and found to be significant. It showed that blending different sand proportions affects 61.89%, 43.98%, and 59.64% of the compressive strengths of 20MPa, 25MPa, and 30MPa of concrete respectively. The concrete from all fine aggregate sources achieved the minimum compressive strength and was recommended for use in the production of normal concrete and residential building construction purposes. However, some good quality sand types produced high compressive strength and would be recommended for use in high-strength concrete work.