Optimum design of the quaternary composite binder considering strength, cost, and electrical resistivity

The optimal design of cementitious materials containing admixtures is one of the important topics in the sustainable development of cement-based materials. In this paper, an experimental study and optimal design study of a quaternary cement paste containing cement, limestone, clay, and slag are carried out. The experimental research included the strength and electrical resistivity at 28 days. The three aspects of strength, cost, and electrical resistivity (durability) were taken into consideration when optimizing the design. The goal of design optimization is to reduce the cost and increase the electrical resistivity as much as possible while meeting the strength level. First, the results of the experiments are summarized as follows: with increasing limestone, clay, and slag content, the 28-day strength showed a decreasing trend, the 28-day electrical resistivity showed an increasing trend, and the cost of paste showed a linear decreasing trend. Second, the optimum design results are summarized as follows: when the strength increases, the cost of composite paste increases from 328.67 to 383.52 CHF/m3, and the satisfaction degree of the cost decreases from 0.97 to 0.44; and the electrical resistivity of composite paste decreases from 34.85 to 15.42 kΩ∙cm, the satisfaction degree of electrical resistivity decreases from 0.99 to 0.39. Third, the trend of the optimal design results is consistent with the trend of the experimental results, and the optimal design method in this paper can be used as an effective tool for the optimal design of structural materials.