Early age stability of concrete pavement by using hybrid fiber together with MgO expansion agent in high altitude locality

Serials of fibers with different elastic modules and MgO expansion agent (MEA) were used to enhance the volume stability of concrete pavement in high altitude localities. Simulation experiments under constant temperature and humidity conditions were carried out to measure early age volume stability of paving concrete by using hybrid fiber and MEA. A test area of concrete pavement was sited to analyses changes of strains inside slabs. The results show that the early age shrinkage of concrete could be effectively compensated by the MEA. However, as the increase addition of hybrid fibers, the expansion of concrete was markedly decreased. Strain records of concrete in test section indicate that the early age volume stability of concrete slabs in high altitude locality could be improved by using hybrid fiber and MEA. Microstructure analysis by scanning electron microscope indicates that the micro-cracking inside of concrete was locally restrained by the surrounding hybrid fibers.