Modeling the Strength Properties of OPC/RPFA Concrete

Abstract

This study developed mathematical models for the prediction of the
Compressive, strength characteristics of OPC/RPFA concrete.
Ordinary Portland Cement (OPC) was replaced with 10% RPFA, 15%
RPFA, 20% RPFA, 25% RPFA and 30% RPFA using a mix ratio of
1:2:4 for the concrete and water-cement ratio of 0.5. The concrete
cubes were removed from the moulds and cured in a water tank for 7,
14, 21, and 28 days. Several tests were conducted on Raffia Palm Fuel
Ash, (RPFA) and OPC/RPFA concrete. The tests included a sieve
analysis test, specific gravity test, slump test, Rapid Chloride
Permeability Test (RCPT), water absorption test, Thermogravimetric
analysis test (TGA), chemical composition test, and compressive
strength test. A design matrix was produced using “Design Expert 10”.
The line of best fit was decided for each of the strength properties. The
developed models showed that the cubic and quartic models of the
independent variable (RPFA) significantly affected the compressive
strength of the material (dependent variable-OPC/RPFA concrete).
The models produced showed an accuracy of 99.28% for the
compressive strength. For the compressive strength properties, there
was a correlation between the predicted values from the models and
the actual values from the experiments. Thus, the models were
validated