Low strength concrete: Stress-strain curve, modulus of elasticity and tensile strength

Material characterization of low strength concrete has significant importance for structural/ seismic performance assessments of existing low-quality structures. The main objectives of this study are to characterize the compressive and tensile behaviors of low strength concrete (LSC). For this purpose, an extensive experimental database is formed by collecting available test results and by conducting new tests. The database combines the compression or splitting tension test results of 165 standard concrete cylinders with the compressive strengths ranging from 3.9 to 20.3 MPa. Firstly, the test results are presented by plotting compressive stress-axial strain curves and by calculating moduli of elasticity, axial strains at peak stresses, ultimate axial strains, and tensile strengths. Secondly, the predictive capabilities of available expressions are demonstrated by comparing them with the corresponding experimental results. Thirdly, simple regression analyses are conducted to define the compressive stress-axial strain curves, and the relationships between compressive, tensile strengths, and elastic modulus. Finally, the prediction capabilities of the proposed expressions are evaluated considering the tests, which were not used to establish the proposed expressions and conducted by other researchers. The comparisons show that the proposed expressions can predict the low strength concrete characteristics with good accuracy.