Non-destructive Evaluation of Self-consolidating High-strength Concrete Incorporating Palm Oil Fuel Ash

Abstract

This paper presents the results of the key non-destructive tests performed on the self-consolidating high-strength concrete (SCHSC) mixes including palm oil fuel ash (POFA) as a pozzolanic supplementary cementing material. Twenty (20) SCHSC mixes were produced with several water-to-binder (W/B) ratios ranging from 0.25 to 0.40. POFA was incorporated in concrete mixes substituting 0%, 10%, 20%, 25% and 30% of ordinary portland cement (OPC) by weight. The non-destructive tests were carried out to determine the dynamic modulus of elasticity and ultrasonic pulse velocity (UPV) of the concretes. In addition, the 28 and 56 days compressive strengths were determined to verify whether the concretes possessed high strength or not. The slump flow of the concrete mixes was also investigated to observe their self-consolidation capacity. Nevertheless, more emphasis was given to observe the effects of W/B ratio and POFA content on the selected non-destructive properties of the concretes. Moreover, the correlations of UPV and dynamic modulus of elasticity with compressive strength were determined. The concrete mixes produced had the required slump flow values (≥ 600 mm) for self-consolidating concrete. The compressive strength of all concretes satisfied the strength requirement (≥ 50 MPa) of high-strength concrete for all replacement levels of OPC. The UPV and dynamic elasticity decreased with higher W/B ratio. POFA was effective in improving the non-destructive properties of concretes up to 20% replacement of cement by weight. Hence, the optimum POFA content was 20% in the context of the present study. Furthermore, the dynamic modulus of elasticity and UPV were strongly correlated with the compressive strength of SCHSC possessing a correlation coefficient of +0.9413 and +0.9709, respectively.