INVESTIGATION ON THE PRODUCTION PROCESS AND QUALITY OF AGGREGATES AND HOLLOW CONCRETE BLOCK: A CASE STUDY OF GEDEO ZONE

Abstract

In order to produce Aggregates and hollow concrete blocks with good quality which satisfy strength and durability requirements, great care have to be taken for their production starting from ingredient selection to finished product. In addition to this, every production process should follow proper scientific procedures. Considering this, investigation focusing on production process and quality of Aggregates and HCB has been conducted in various Aggregate and HCB production sites located in Gedeo Zone. The research is carried out by observing the production process, collecting information on method of production through interviews and performing different tests in the laboratory to evaluate the quality of the products. Based on the findings, conclusions are drawn and recommendations are forwarded. The findings of the investigation have shown that in most of Aggregate production site process of production is not modern and scientific. From the investigated crushing sites the Wenago and Golla crushing sites follows the best production process and also the quality of aggregates produced also better than the Waleme and the Mechisho crushing sites, especially the grading requirement was not satisfactory and the aggregates are coarser in Waleme and Mechisho Aggreagtes. All fine aggregate sources investigated in this research were natural sand excavated from river bed and the Gidabo and the Gollelicha sands were unsatisfied in grading requirement, Kilkile sand was better grading and also it passes the organic impurity test and the other two did not. Based on their quality C-30 concrete mix was prepared and the compressive strength test was performed. The mix prepared using Wenago aggregate and Kilkile sand achieved 34.85MPa 28th days compressive strength and the other mix prepared using the Waleme aggregate and Gollelicha sand achieved 28.40MPa. In HCB production sites laboratory tests were not conducted for all ingredients used for production of hollow concrete blocks and they use nominal mixing proportion, no mix design is drown based on materials property. The main products in all production sites is class C and it does not fulfill the standard provided in its compressive strength and block density. In addition to this, handling of those ingredients was very poor, and production process also not conducted properly as specified in the recommended standards.