LAUSR

Abstract The paper presents the results of the study of the influence of the addition of retarding superplasticising admixture based on triisobutyl phosphate and modified phosphonates on the amount of heat generated by hardening shielding concrete. A four-point measurement of the heat generated during the hardening of concrete with an admixture dose of 0, 0.5, 1.0 and 2.0% by weight of the cement was made and the concurrent measurement of the heat released by the hardening cement paste was measured with an isothermal calorimeter. Based on the results from the calorimeter, the effect of the admixture on the temperature field in the hardening concrete mass elements was simulated for different aggregates. The results indicate that the admixture clearly lowers the temperature gradient in hardening mass concrete. In the simulations, the most clear effect was achieved in the case of concrete with barite aggregate, where the gradient value was reduced from 10°C/m to 8°C/m for an admixture content equal to 2.0%.