Evaluation of the effect of volcanic ash on the properties of concrete
Effect of volcanic ash on the properties of concrete was assessed in the study. Preliminary tests were carried out on the different properties of materials used. The concrete samples were prepared using 0%, 5%, 10%, and 15% volcanic ash replacements and nominal mix of 1:2:4 with a 0.5 w/c ratio. Concrete sample specimen was subjected to workability test. Thereafter, Cube mould of size 100mm x 100mm x100mm and cylinder mould of size 200mm x 100mm were used to cast a total of 405 concrete samples, 162 cubes were used to assess compressive strength test while 162 cylinders were used to determine the tensile strength by the split tensile method. The specimens were cured and tested at 7, 14, 21, 28, 56 and 90 days. The results show setting time and soundness test of Miango volcanic ash satisfied the necessary requirements. Also, increase in compressive strength and split tensile strength of about 7.99% and 6.14% respectively, for concrete samples with 10% volcanic ash replacements after 28days of curing. It was concluded that Miango volcanic ash retards the setting time of concrete and enhances the properties of concrete. Hence it was recommended that it should be used to produce a strong and dense concrete and serve as an admixture.
Keywords: Concrete, compressive strength, volcanic ash, partial replacement, workability