Effect of zeolite on waste based alkali-activated inorganic binder efflorescence

Alkali-activated inorganic binder has been a research hot spot in the field of building materials owing to its wide range of raw materials, low energy consumption, less pollution and superior performances. The bicarbonate salt weathering is one of prime cause of deterioration of porous materials. To inhibit the efflorescence of waste based alkali-activated inorganic binder, 5A zeolite powder was blended and the efflorescence inhibition mechanism was analyzed. Effect of 5A zeolite content on the mechanical properties, bicarbonate ions concentration, pH value and pore size distribution of the obtained alkali-activated inorganic binder were investigated. The results showed that the compressive strength and bending strength of the waste based alkali-activated inorganic binder are improved with adding moderate content of 5A zeolite powder, and the pH value of specimens decreases with increasing amount of 5A zeolite powder content, the average pore size of samples decreases with adding moderate content of 5A zeolite powder due to its micro-aggregate filling effects. The efflorescence of waste based alkali-activated inorganic binder is effectively reduced with the adding of 5A zeolite powder, and the inhibition mechanisms mainly are that the special ion-exchange properties and micro-aggregate filling effects.