Abstract:
Cement is one of the main constituent materials in concrete production. From production of
cement large amount of CO2 emitted to the atmosphere. The utilization of comcent is increasing
over time and this causes an environmental impact. Replacing this material with other eco friendly cementing materials is a global concern. Different researchers introduce alkali activated concrete using local geo-material and an industrial by-product as a cementing agent
without influencing the concrete property.
Therefore, this research aimed to investigate the capacity of alkali-activated concrete made from
locally available geo-material (white soil ‘Nech Afer’ )as a partial replacement of Portland
pozolanic cement in C-20/25 concrete. The pozolanic nature of the geo-material (white soil
‘Nech Afer’) was examined by chemical composition test. A 10%, 20%, 30%, 40%, and 50%
replacement was carried out and investigated for workability, compressive strength, and
splitting tensile strength test and compared with the control sample.
From this research, it was observed that white soil ‘Nech Afer’ has a pozolanic property.
Therefore, using white soil ‘Nech Afer’ with an alkali activator in partial replacement of cement
in geopolymer concrete production was possible. The compressive strength test results in
40.38MPa at 10% replacement, 28.33Mpa at 40%, and 22.95MPa at 50% replacement were
obtained. Whereas, for the control sample, 28.75MPa compressive strength results were
obtained on the 28th day. But, the workability of the alkali-activated white soil ‘Nech
Afer’concrete decreases as the percentage of replacement increases from the fresh property of
concrete.
Therefore, it can be concluded that the optimum percentage of replacement of cement with
alkali-activated white soil ‘Nech Afer’ in C-25 concrete is 40%. And, it was observed that 50%
replacement of cement with alkali-activated white soil ‘Nech Afer’ may use in low-grade
concrete production. Alkali-activated white soil ‘Nech Afer’ concrete has low workability
compared to normal fresh concrete.
