Quantitative Analysis of Concrete Mechanical Properties with Ultrasonic Shear-Wave Tomography

Abstract

Abstract Ultrasonic shear-wave tomography (UST) offers a promising nondestructive approach for evaluating the internal condition and mechanical properties of concrete. Although its qualitative capability to detect internal defects is well established, limited research has investigated the quantitative relationship between shear-wave velocity and key mechanical parameters, such as compressive strength and elastic modulus. This study presents experimental results from five full-scale concrete slabs ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="100 c m times 50 c m times 30 c m" display="inline" overflow="scroll"> <mml:mn>100</mml:mn> <mml:mtext> </mml:mtext> <mml:mi>cm</mml:mi> <mml:mo>×</mml:mo> <mml:mn>50</mml:mn> <mml:mtext> </mml:mtext> <mml:mi>cm</mml:mi> <mml:mo>×</mml:mo> <mml:mn>30</mml:mn> <mml:mtext> </mml:mtext> <mml:mi>cm</mml:mi> </mml:math> ) and companion cylinders representative of construction practices in Northwest Iran. Mechanical testing and UST measurements were conducted to analyze how material properties and internal anomalies—such as voids and cracks—affect shear-wave propagation. The findings revealed strong correlations between shear-wave velocity and both compressive strength and elastic modulus. Predictive models were developed, with maximum errors of 9% for compressive strength and 5% for elastic modulus, with statistical validation confirming their reliability ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="upper R upper M upper S upper E equals 1.19 upper M upper P a" display="inline" overflow="scroll"> <mml:mi>RMSE</mml:mi> <mml:mo>=</mml:mo> <mml:mn>1.19</mml:mn> <mml:mtext> </mml:mtext> <mml:mi>MPa</mml:mi> </mml:math> , <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="upper R squared equals 0.967" display="inline" overflow="scroll"> <mml:msup> <mml:mi>R</mml:mi> <mml:mn>2</mml:mn> </mml:msup> <mml:mo>=</mml:mo> <mml:mn>0.967</mml:mn> </mml:math> for strength; <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="upper R upper M upper S upper E equals 1,098 upper M upper P a" display="inline" overflow="scroll"> <mml:mi>RMSE</mml:mi> <mml:mo>=</mml:mo> <mml:mn>1,098</mml:mn> <mml:mtext> </mml:mtext> <mml:mi>MPa</mml:mi> </mml:math> , <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="upper R squared equals 0.977" display="inline" overflow="scroll"> <mml:msup> <mml:mi>R</mml:mi> <mml:mn>2</mml:mn> </mml:msup> <mml:mo>=</mml:mo> <mml:mn>0.977</mml:mn> </mml:math> for modulus) Additionally, a deliberately introduced crack in specimen M375-C was successfully detected using multiangle tomographic reconstruction, demonstrating UST’s diagnostic capabilities. Building on the demonstrated measurement stability of shear-wave techniques reported in previous studies, the present work extends their application to single-sided, full-scale slab testing, achieving high prediction accuracy ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="upper R squared greater than 0.96" display="inline" overflow="scroll"> <mml:msup> <mml:mrow> <mml:mi>R</mml:mi> </mml:mrow> <mml:mrow> <mml:mn>2</mml:mn> </mml:mrow> </mml:msup> <mml:mo>&gt;</mml:mo> <mml:mn>0.96</mml:mn> </mml:math> ) and field-ready reliability. Compared to previous empirical approaches, the proposed models provide significantly improved accuracy and consistency for the quantitative evaluation of concrete mechanical properties.