Durability properties of γ-radiation-induced polymer-modified mortar. I. Effect of sodium sulfate

The influence of sodium sulfate solutions on the physicomechanical properties of neat and modified cement mortar has been investigated. The samples were immersed in sodium sulfate solutions having different concentrations between 0.5 and 2.5% and immersion times from 20 to 100 days. The effect on the compressive strength, weight loss, bulk, density, and water absorption and the microstructure (scanning electron microscopy) were studied. The results indicate that the compressive strength and loss in weight decrease with the increase in sodium sulfate concentration and immersion time. The bulk density increases and then decreases as a result of the increase in sodium sulfate concentration and the time of storage, whereas water absorption behaves in an opposite direction, probably due to partial dissolution of the hydrated products. SEM study showed the formation of new products and voids between the particles were pronounced.