Influence of dually mixing with latex powder and polypropylene fiber on toughness and shrinkage performance of overlay repair mortar

摘要

The influence of dually mixing of polymer latex powder and polypropylene fiber on the toughness and the shrinkage of the overlay repair mortar (ORM), was investigated. To this end, the L-9(3(4)) orthogonal test scheme was designed to evaluate the strength, the ratio of flexural strength to compressive strength (RFSCS), and shrinkage ratio of the mortar at different ages and to optimize the mix parameters of ORM with minimum shrinkage, high toughness and strength. Fitting and regression analysis were conducted to establish the shrinkage model of ORM, and the significance was assessed by a run test. The results indicate that the latex powder and the polypropylene fiber can significantly improve the toughness, but weaken the strength of the mortar to some extent. The exponential relation between the shrinkage ratio and time is significant at a significance level of alpha = 0.01. The comprehensive performance of the mortar of prioritizing the volume stability is optimal when the amount of polymer is 2.5%, length of the fiber is 9 mm, amount of the fiber is 0.2%, and content of silica fume is 2.5%. Moreover, it is suitable to be used as an overlay repair material for concrete pavements. (C) 2020 Elsevier Ltd. All rights reserved.