Effect of compounding conductive materials on the mechanical properties of concrete and the microscopic mechanism

Abstract

After adding conductive materials into the concrete matrix, cracks can be monitored in real-time through the change of concrete resistance when cracking. However, adding conductive materials will affect the working and mechanical properties of concrete. Therefore, this paper studied the influence rule and failure characteristics of the addition of conductive materials such as steel fiber and nanocarbon black on the mechanical properties of concrete. Combined with the performance index of the mix, it comprehensively determined the optimal dosage range of different types of steel fiber and nanocarbon black under the single mixing factor. Then, the orthogonal test method of three factors (different kinds of fiber, different contents of steel fiber, and different contents of nano carbon black) at four levels are used to test and study the mechanical properties of concrete. Through the analysis of the test results, the primary and secondary factors of conductive materials affecting the strength of concrete and the optimal dosage are obtained, and the failure mechanism is analyzed from the microscopic level. Finally, a structural model of the cracking resistance mechanism of conductive materials is proposed.