Authors : U. K. Unamba; E. S. Nwajagu; J. Abutu; O. J. Agbo-Anike
Volume/Issue : Volume 6 - 2021, Issue 8 - August
Scribd : https://bit.ly/2Vbbwzi
The increasing demand of cement in
construction has raised lots of sustainability concerns.
However, the application of agricultural wastes such as
coconut shell ash (CSA) as a partial replacement of
cement holds great prospects for sustainability in the
construction industry. Reliable and rapid model
prediction of concrete strength is capable of increasing
the pace of construction without compromising the
quality control measures.Coconut shells were collected
and burnt after which the resulting ash was subjected to
fluorescence method of analysis. With the use of a
concrete mix design ratio of 1:2:4 and water binder ratio
of 0.6, a total of 36 concrete cubes of sizes 150mm x
150mm x 150mm were cast using varying OPC – CSA
ratio 100:0, 95:5, 90:10, 80:20. The cubes was cured for 7,
14 and 28 days and thereafter crushed to test the
compressive strength. The experimental data was
subjected to regression analysis using IBM SPSS
Statistics software. The multiple regression model showed
that the general form of the equation for the prediction of
the compressive strength of concrete from percentage
replacement, curing age and density is: Compressive
strength of concrete = 0.44 – 0.162 (percentage
replacement) + 0.008 (curing age) + 0.006 (density). The
result showed that the percentage replacement
contributed more to the model followed by the curing age
and the density. The experimental result showed that for
20% replacement of cement with CSA, the average
compressive strength for 7, 14 and 28 days of curing are
9.80 N/mm2, 11.50 N/mm2 and 13.50 N/mm2. While the
corresponding values obtained using the regression model
are 9.892 N/mm2, 10.374 N/mm2 and 12. 58 N/mm2.
From the above data, it is observed that the experimental
results is slightly different from the analyzed results.
Keywords : Sustainability, Regression Model, Concrete, Compressive Strength, Multiple Regression.