Assessment of quality of sand sources and the effect on the properties of concrete (the case of bahir dar and its vicinities)

Abstract

The main purpose of this study is to assess the quality of sand sources, the effect on workability, compressive strength and cost of concrete in and around Bahir Dar. Initially, questionnaires and interviews were made with stakeholders and suppliers. After that, different natural sand samples were collected from 13 sand supply locations. Then, their physical and chemical properties were tested in laboratory. Finally, mix design is prepared for a normal strength concrete. From the survey results, it was found that, about 87.5% of the stakeholders use Arno, Tana, Tis-Abay, Addis-Zemen, Andasa and Rib as the major sand sources out of the thirteen around Bahir Dar and its vicinities. And about 67.5% of the stakeholders use more than one source. Trial mix designs were prepared for concrete production focusing on six of the common sources. The results have shown that, for normal strength concrete, the blended sand from six common sand sources met workability of the fresh concrete and there is no significant difference in compressive strength of concrete with blended sand. Finally, the finding has indicated that, all the thirteen supply locations have quality problems; especially in gradation as well as, in silt and clay contents. Based on the research outcome blending Addis-Zemen sand with that of Ribb sand incurs the least cost, while at the same time fulfilling requirements of fresh and hardened concrete.