Method for Enhancing Durability of Sticky Rice Mortar Under the Coupling Effect of Chloride Salt Erosion and Freeze-Thaw Cycle

For improving the frost damage caused by salt efflorescence of traditional sticky rice mortar applied in the restoration and reinforcement of ancient masonries, a kind of modified sticky rice mortar composite material was obtained by adding 12.5%, 25% and 50% metakaolin and 1% flax fiber. Based on the mechanical strength, mass loss and relative dynamic elastic modulus of elasticity, the application performance of modified mortar was studied in detail. By means of infrared diffraction, X-ray powder diffraction and scanning electron microscopy, the perfor-mance evolution mechanism of modified mortar under normal curing, freeze-thaw aging and chloride corrosion freeze-thaw cycle coupling was studied. The results show that the strength, frost resistance and salt resistance of mortar can be significantly improved by mixing flax fiber and metakaolin. The hydrated gel C-S-H and C-A-H produced by metakaolin can solidify chloride ions to form Friedel salt to resist pore destruction and enhance the frost resistance of mortar in chloride environment. The durability index increases slightly with the addition of flax fiber, and increases first and then decreases with the addition of metakaolin. Among them, the reinforcement method of mixing sticky rice ash with 1% flax fiber and 25% metakaolin is the best. © 2021, Materials Review Magazine. All right reserved.