Optimization of the composition of a blended binder for hot dry climate concrete

A hot dry climate has a significant impact on the properties of concrete. The paper presents the results of experimental studies in the development of the composition of a composite binder consisting of Portland cement and a dolomite microfiller obtained by activating the screening of dolomite crushing in a ball laboratory mill. The content of dolomite filler in Portland cement was 10, 30 and 50%. It has been shown that dolomite micron filler, when its content in the binder is more than 10%, reduces compressive strength. It has been found that dolomite filler reduces water consumption, reduces setting time and reduces shrinkage of the composite binder during hardening. To optimize the composition, a two-factor composite (rotatable) experiment with a quadratic model was used, which ensures maximum strength when the required technological parameters are achieved. The optimal composition of the composite binder, consisting of 67% Portland cement and 23% dolomite filler with a specific surface area of 600 cm2/g, has been established. Therefore, to increase the crack resistance of concrete, the use of dolomite filler as part of a composite binder for concrete in dry, hot climates is relevant, due to its low-er shrinkage during hardening.