Real-Time Monitoring of Concrete Strength Evolution Using Embedded Wireless Sensors

Abstract

The maturity technique offers a practical approach for forecasting early-age strength development. This study aimed to evaluate the accuracy of Giatec's SmartRock sensors by comparing their measurements with conventional specimen test results derived from the maturity index. Twelve concrete combinations were evaluated, with compressive strengths ranging from 20 to 45 MPa. The nine concrete mixes were designed with varying proportions of cement, sand, coarse aggregate, water, and admixture, as summarised in Table 1. The cement content ranged from 290 to 430 kg/m³, water-to-cement ratios varied from 0.27 to 0.51, and admixture dosages ranged from 0.5% to 1.2% by weight of cement, depending on the desired strength level (20-63 MPa). Cylinder tests performed at 1, 3, 7, 14, and 28 days provided the data necessary to calibrate the maturity–strength relationships. The resulting correlations between compressive strength and maturity index showed excellent accuracy, with coefficients of determination (R²) ranging from 0.986 to 0.999 across all twelve mixes (20-45 MPa). These results confirm that the SmartRock maturity method reliably predicts early-age strength and offers real-time assessment of in-situ concrete performance. The best-fit Vipulanandan models yielded coefficients of determination (R²) ranging from 0.986 to 0.999, demonstrating excellent agreement between sensor-predicted and laboratory-measured strengths. Predicted early-age strengths (3–7 days) differed from test values by less than 5%, confirming the reliability of the SmartRock system for field applications. The study concludes that the maturity method, when properly calibrated, provides a robust and non-destructive means to predict in-place concrete strength in real time, enabling faster formwork removal and improved construction quality control.