Influence of superplasticizer additive on the strength of cement stone during wetting–drying cycles

Abstract

This article discusses the issues of durability of reinforced concrete structures exposed to drying–wetting cycles. Transport structures are under the constant wetting and drying cycles, but rarely completely dry out, as the saturation process occurs faster drying. Such cycles cause moisture migration inside the concrete, which leads to leaching of calcium hydroxide Ca (OH)2. The structure of the cement stone changes over time, and the dissolution of cement hydration products additionally leads to a strength decrease. Were tested the influence of the alternation of cycles of water saturation and drying of concrete on tensile strength, as the most sensitive characteristic to changes in the structure of the material. Since at present most concretes are manufactured using plasticizing additives, the tests were carried out with different content. The studies show that regardless of the amount of plasticizing additive in the samples, the flexural strength decreases. The compressive strength gradually increased, which is probably due to the ongoing process of hydration of the cement grains.