Umudike Journal of Engineering and Technology

Michael Okpara University of Agriculture, Umudike


PREDICTION OF COMPRESSIVE STRENGTH OF SANDCRETE BLOCKS BLENDED WITH FLY ASH AND PERIWINKLE SHELL ASH

Ojinta, P. E.
Department of Civil Engineering, Michael Okpara University of Agriculture, Umudike, Abia State

Ngene, B. U.
Department of Civil Engineering, Michael Okpara University of Agriculture, Umudike, Abia State

Ibe, K. C.
Department of Civil Engineering, Michael Okpara University of Agriculture, Umudike, Abia State



ABSTRACT

This study aimed at prediction of the compressive strength of cement blended Fly Ash-Periwinkle shell ash sandcrete blocks using Scheffe’s simplex theory. A total of ninety (90) fly ash-PSA solid sandcrete blocks of dimensions 450 x 125 x 225 mm were cast, consisting of three (3) blocks per mix ratio and for a total of thirty (30) mix ratios, comprising of fifteen (15) mix ratios each for both trial and control mixes. The first fifteen (15) mixes were used to develop the model while the other fifteen (15) were used to validate the model. The model predicted results were compared with the one obtained from the laboratory. The results showed that the percentage differences ranges from 8.16% to 15.34%.  The model predictions were tested for adequacy using statistical Students t-test at 95% confidence level, and were found to be adequate. Computer program was developed for the Scheffe’s model using Visual Basic 6.0. The mathematical model results compared favourably with the experimental results. The optimum experimental compressive strength of the blended sandcrete after 28 days of curing was found to be 4.68N/mm2 for experimental compressive strength while the model predictive compressive strength recorded an optimum compressive strength of 4.26 N/mm2.


Keywords: Sandcrete blocks, compressive strength, cement, Fly Ash, Periwinkle Shell Ash


https://doi.org/10.33922/j.ujet_v11i2_6
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Published
Monday, July 14, 2025

Issue
Vol. 11 No. 2, December 2025

Article Section
GENERAL

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