ПІДВИЩЕННЯ РАННЬОЇ МІЦНОСТІ БЕТОНУ ЗАЛІЗОБЕТОННИХ ШПАЛ ЗА ДОПОМОГОЮ ДОБАВОК СУПЕРПЛАСТИФІКАТОРІВ

Abstract

The influence of superplasticizer-polycarboxylate additives on the early concrete strength of reinforced concrete sleepers has been studied. It has been established that the use of superplasticizers-polycarboxylates can increase the early strength of concrete after heat treatment, but each additive must be tested for compatibility with the cement used. Electron microscopic studies have not revealed a significant change in the structure of hydration products due to the use of superplasticizers-polycarboxylates. The scheme of development of the cement setting process and the initial stage of hardening without additives or with additives of superplasticizers-polycarboxylates has been developed, which explains their accelerating effect consisting in reduction of water consumption, decrease in the primary thickness of interlayers between cement particles, mineral additives, aggregates, their filling with hydration products. As a result of potentiodynamic and microscopic studies it was found that the addition of superplasticizer-polycarboxylate has no corrosive effect on steel reinforcement. It was established that to obtain transfer strength of 32 MPa in 24 hours it is necessary to provide low-heat curing at the temperature of isothermal curing at 40-50°С, and in 2 days it is achieved with natural curing. It is recommended as the cost of energy carriers and additives changes, to monitor the economic efficiency of the reduction of the modes of TIE due to their use. The formula of economic efficiency of using additives to reduce the energy intensity of the production of reinforced concrete sleepers has been proposed.