Research On Composition And Property Of Paving Cement Concrete

Mechanical performance, frost resistance and abrasion resistance of concrete with fly ash, air entraining agent and four kinds of inorganic salts including sodium sulfate, sodium nitrite, calcium nitrite and sodium chloride are mainly studied in this paper.The performance of concrete at the later age (after 60 days) is improved when fly ash is added into concrete, and the abrasion resistance of concrete is perfect at 28 days. Entraining air into concrete, the compressive strength is reduced but the flexural strength is improved when the air content less than 5.5%. The frost resistance of air entraining concrete is improved significantly, while the abrasion resistance of concrete is not decreased. Different kind of inorganic salts have different influence on the performances of concrete. Sodium sulfate can decrease the compressive strength of concrete but increase the flexural strength. Sodium nitrite can decrease the compressive strength of concrete but increase the flexural strength obviously. Calcium nitrite can increase the compressive strength of concrete and decrease the flexural strength. Sodium chloride can decrease the compressive strength of concrete and increase the flexural strength lightly. The influence of inorganic salts on mechanical performance of air entrainment concrete is similar with non-air entraining concrete. All those inorganic salts can improve the frost resistance of concrete except calcium nitrite. However, the frost resistance of air entraining concrete decrease after adding salts. Sodium nitrite and sodium chloride decrease the abrasion resistance of concrete, and other salts have little effect on the abrasion resistance of concrete. The abrasion resistance of air entraining concrete has little changes when salts added into concrete.