Title: Prediction and Optimization of Self-Consolidating Concrete Properties

Author(s): Walid E. Elemam, Ahmed H. Abdelraheem, Mohamed G. Mahdy, and Ahmed M. Tahwia

Publication: Materials Journal

Volume: 119

Issue: 1

Appears on pages(s): 91-104

Keywords: central composite design (CCD); compressive strength; flexural strength; optimization; response surface methodology (RSM); selfconsolidating concrete (SCC)

DOI: 10.14359/51733149

Date: 1/1/2022

Abstract:
This investigation aims to predict and optimize self-consolidating concrete (SCC) characteristics containing fly ash (FA), silica fume (SF), and limestone powder (LP) as part of the cement by mass in the total powder content. Total powder content (P), proportion of FA, proportion of SF, proportion of LP, water-powder ratio (w/p), and proportion of high-range water-reducing admixture (HRWRA) were the input parameters of the mixtures, and the desirable responses were slump flow, 7- and 56-day compressive strength, and flexural strength. A total of 90 concrete mixtures were designed using the central composite design (CCD) concept in Minitab 18 statistical software under response surface methodology (RSM) to simulate and optimize the variables and responses of models. Results showed that high relation can be developed between the responses and the constituent materials in predicting characteristics of SCC, removing the drudgery of repetitive laboratory testing and enabling rapid decision-making for building applications. The slump flow increased with the increase in total powder content, FA content, w/p, and HRWRA dosage and decrease in SF content, while LP has insignificant effect on slump flow results. The increase in partial replacement of cement by FA decreased the compressive strength of mixtures at early ages. The higher values of compressive strength were observed when SF incorporated in higher levels, and flexural strength also enhanced with the increase in SF content.