EFFECT OF LOCAL SAND SOURCE AND COARSE AGGREGATE PRODUCTION ON CONCRETE PROPERTIES: A CASE OF HAWASSA CITY

Abstract

Concrete structures are integral parts of modern civil infrastructures constituting a large portion of the national wealth of any country. Concrete consists of 60–75% volume with aggregates. Therefore be expected to have most suitable aggregate properties utilization in concrete are reducing volume change, improving the concrete properties against applied load and environment on concrete. Currently, it is normal practice to see the traditional method of fine aggregate production and both traditional and modern means of coarse aggregate production in Hawassa city to produce concrete. In this study, an investigation has been performed on properties of sand sources from Bilate, Dimtu, and Halaba while coarse aggregate production from Waye Bonge Quarry, Daete Quarry, and Derago Quarry and their effect on fresh and hardened concrete properties. This experimental investigation has been performed on nine concrete batches for each C-30 and C-50 concrete grades with different selected quarries that supply aggregate to Hawassa city. The fresh concrete property was done through concrete workability in terms of slump cone and compaction factor tests. Hardened concrete properties were done through concrete hardened density, compressive strength, splitting tensile strength, water absorption, sulfate attack resistance, and chloride attack resistance tests. For hardened density, compressive strength, and durability tests 150mm concrete cube specimens and for splitting tensile strength test cylinder specimens (150mm diameter and 300mm length) were used. Detailed experimental test results of different aggregates and concrete properties were presented, analyzed and discussion was done based on standards and previous related literature to investigate aggregates properties and their effect on concrete properties. The results show that all sand sources classified under poorly graded sand with high silt content; coarse aggregate production with poorly graded and high percentage of flaky and elongated aggregate in concrete negatively affects the workability, strength, and durability of concrete. It is recommended that aggregate producers should give proper attention to producing consistent and quality products in terms of relevant parameters, which are compatible with the standard requirements