Strength Prediction and Correlation of Cement Composites: A Cross-Disciplinary Approach

We present a cross-disciplinary approach applied to the strength prediction and correlation of cement composites in this paper. The empirical models for predicting flexural and compressive strengths of a kind of fiber reinforced cement composites, known as engineered cementitious composites (ECCs), were first developed. Nonlinear regressions were applied to the measurement data of a destructive compression test and four-point bending test. Each of these tests was conducted on 36 specimens at growing ages (3, 7, 14, and 28 days), wherein three mixes of ECC (PE1, PE2, and PE3) were prepared for each test. Each mix had different water-to-binder (w/b) ratios of 0.20, 0.255, and 0.30 whereas the total volume of each mix remained the same. The correlations among flexural strength, compressive strength, and electrical conductance of ECCs were then developed based on the early-age measurement using the microwave non-destructive test (mDNT). The primary objective of this research is to study the relations between flexural strength and compressive strength of ECC specimens under the influence of small deviations in w/b ratio. The secondary objective is to predict the strength growth of ECCs with the microwave effective conductance. The correlation results show that the flexural strength behaves as a quasi-linear function with increasing compressive strength, which has been verified by using direct measurement data. This cross-disciplinary approach highlights the effectiveness of the mDNT in predicting the mature strengths of ECCs at early ages.