Application of cement hydration heat inhibitors to control thermal cracking in massive concrete structures

Introduction. The problem of temperature cracking due to cement hydration in massive concrete structures attracts the attention of many domestic and foreign scientists. At present, there are many measures to prevent the formation of temperature cracks during concrete hardening. It is possible to divide them into two main classes. The first one is technological measures in the process of construction. The second direction is related to the optimization of concrete composition, including the use of various additives. One type of such additives are cement heat release inhibitors. Their use makes it possible to reduce heat release from cement hydration at the early stage of concrete hardening. This greatly reduces the risk of thermal cracking. The method is quite new and has not been fully investigated to date.Materials and methods. In this work, the influence of cement hydration heat inhibitor addition on the probability of thermal cracks formation during the concreting of massive concrete structures was evaluated using the finite element method. Calculations of the temperature regime and thermal stress state of the concrete mass after its erection were carried out. Two variants of concrete mixture composition were considered: the usual composition — without the use of inhibitor and the composition with the addition of heat of hydration inhibitor. Numerical studies were carried out on the basis of the finite element method using the Midas civil 2019 software package.Results. As a result of numerical solutions for two variants of concrete compositions, the distribution of temperature and temperature stresses in the erected concrete mass was obtained. The risk assessment of temperature cracking is given.Conclusions. Heat of hydration reduction inhibitors are effective in reducing the hydration temperature in massive concrete structures. The addition of 1 % TRI of cement weight in massive concrete structures significantly reduces the risk of thermal cracking.

Temperature reduction inhibitor (TRI), maximum temperature, temperature field, concrete mass, cement hydration, temperature crack