Abstract:
As the demand for infrastructure increases, there is a corresponding increase in material
consumption. High rise structures require high strength concrete to withstand high
compressive loads and increase their design life. To achieve this, the highest quality of fine
aggregates, such as river sand, is used to improve the concrete strength. However, this has
resulted in a scarcity of river sand in developing countries over time. In order to reduce this
impact, pond ash has been partially used to replace fine aggregate.
The objective of this study was to examine how partially replacing fine aggregate with pond
ash affects the workability and mechanical properties of high strength concrete.
For the C-45/55 grade of concrete, a control mix and five different mixes were prepared,
each containing a replacement of fine aggregate with pond ash ranging from 0% to 25%. The
workability of the fresh concrete was measured by its slump, which was found to decrease as
the percentage of pond ash increased. This is because pond ash has a high absorption
capacity.
The mechanical strength test results for high strength concrete, where fine aggregate was
partially replaced by pond ash, showed that there was an increase in compressive strength at
28 days by 5.40% for 5% of pond ash, 1.30% for 10% of pond ash, and a reduction in
compressive strength by 2.26% for 15% of pond ash, when compared to the ES EN 1992
standard. Similarly, the splitting tensile strength test results at 28 days showed an increase in
strength by 3.64% for 5% of pond ash, 0.81% for 10% of pond ash, and a reduction in
strength by 3.04% for 15% of pond ash, compared to the ES EN 1992 standard.
Therefore, it can be concluded that replacing up to 10% of fine aggregate by weight with
pond ash fulfils the compressive strength and splitting tensile strength requirements of the ES
EN 1992 code of standards.
