Effect of glass powder on compressive strengths and microstructure of ultra-high-performance concrete

The most common methods for dealing with waste glass are landfilling or incineration, which cause wastage of resources. The method for preparing ultra-high-performance concrete (UHPC) by partially substituting cement with glass powder (GP) was herein studied in order to realize the high value treatment of waste glass. The experimental results indicated that incorporation of 5% GP brought the highest compressive strengths for UHPC, which was increased by 5.11%, compared to the control UHPC in 28 days. Furthermore, the later-stage compressive strengths for UHPC at 60 days increased continuously with incorporation of 10% and 15% GP, respectively, indicating that GP does not hinder the development of strengths. Using multiple micro testing techniques, it was indicated that, GP exhibited pozzolanic reaction and dilution effect, which can enhance cement hydration and increased the amount of hydration products. Thus, the microstructure of UHPC with appropriate amount of GP was significantly improved. In addition, the CO2 emissions and production costs for UHPC decreased steadily with increased GP content. Compared to the control UHPC, UHPC with 15% GP exhibited decreased by 1.47% in production costs and 7.39% in CO2 emissions.