Effect of the water/cement ratio on mechanical and physical degradation of concrete in sulfate environment

In this study, the physical and mechanical properties of concrete are investigated. Two conditions of concrete were considered: 1-undegraded condition and 2-degraded condition by a chemical leaching mechanism. The chemical leaching condition is achieved by immersing the concrete material in sulfuric acid (H2SO4). For the first condition, concrete properties depend only on the characteristic age of concrete, defined as 28 days. For the second condition, these properties depend on immersion time and the concentration of the test solution. In this work, the experimental tests were carried out on the most commonly used concretes with three water/cement (W/C) ratios: 0.45, 0.5, and 0.7, made up of limestone aggregates with a maximum diameter of 16 mm, bound by Portland cement paste with 55 MPa of mechanical strength. In order to determine the physical and mechanical properties of concrete, specific experimental devices were designed and produced for this study's needs. Then, for the different degradation conditions, concrete samples were subjected to several experimental tests. The influence of the chemical reaction on the physical and mechanical properties of concrete was analyzed. Chemical degradation affects the physical and mechanical behavior of concrete in many ways. A chemical reaction increases the porosity of the concrete. The variation in porosity directly influences the tensile and bending strengths.