ESTUDO DA HIDRATAÇÃO DE PASTAS DE CIMENTO DE ALTA RESIST̂ENCIA CONTENDO POLÍMERO SUPERABSORVENTE (PSA), PELA TÉCNICA DA DIFRAÇÃO DE RAIOS-X (DRX).

The use of High Strength Concrete (HSC) provides advantages in construction, such as high strength and durability. Denser microstructure, caused by low water/cement ratio and high consumption of cementitious material, make this concrete less permeable and less porous. However, HSC suffers volumetric changes, especially the autogenous shrinkage, which is critical in the early ages when the material is more susceptible to cracking. A strategy to mitigate this shrinkage is to achieve internal curing of concrete by the addition of superabsorbent polymers (SAPs), an slightly characterized material for use in construction. This paper had as objective the study of addition of PSA in high strength cement pastes as internal curing agents, through the technique of X-ray diffraction (XRD) over time (1, 3, 7 and 28 days). Was analyzed the hydration of a paste with addition of 0.30% SAP and water/cement ratio of 0.30. In this paste was added water for internal curing, with a total water/cement ratio of 0.35. The results were compared with two reference pastes with water/cement ratios of 0.30 and 0.35, both without the addition of SAP. Although the method of analysis does not allow quantitative considerations about the hydration products, the results indicate that the addition of SAP appears to increase pozzolanic activity, particularly within the first 7 days.