Influence of sulfate attack on chloride ion ingress in high-performance concrete

Abstract EN

This study was carried out to evaluate the influence of sulfate attack on chloride ingress in high-performance concrete.

After water curing, the specimens were placed in three different test solutions, having the following compositions : 5.0 % NaCl, 5.0 % NaCl + 0.5 % Na2SO4 and 5.0 % NaCl + 20 % Na2SO4.

The deterioration of concrete due to combined attack was evaluated through change in compressive strength and expansion measurements.

The concentrations of free chloride and sulfate penetrating specimens through diffusion were measured periodically, up to 18 months.

Microstructure analysis was also carried out through X-ray diffraction and Scanning electron microscope.

The experimental results showed that the presence of sulfate in the combined solution decreased the free chloride content at early exposure period, but the opposite was observed at latter exposure period.

Addition of silica fume may significantly improve the resistance of concretes to combined attack.

The content of C3A in cement used in concrete proved to be an important factor in the concrete performance when subjected to combined attack.

The high-performance concrete with its superior mix design (cement content and w / c ratio) confirmed its effectiveness in withstanding the influence of combined attack on concrete.