Abstract
In order to solve the problem of efficient and effective repair after brittle cracking of concrete on road and bridge deck pavements, and to consider the resource utilization of coal gangue solid waste, the river sand was replaced by coal gangue and a high ductile concrete rapid repair material (HDCRRM) was prepared through performance optimization design. First, the fluidity and compressive strength of materials mixed with different amounts of sulfoaluminate cement (SAC), fly ash, lithium carbonate, calcium hydroxide, calcium formate, sand-binder ratio, water-binder ratio and polycarboxylate superplasticizer were studied, so as to determine the preferred benchmark mix proportion. Then, the replacement rate of coal gangue was optimized to develop HDCRRM. Test results show that the reduction of SAC cement and the increase of fly ash content can weaken the compressive strength of material. The rational design content of lithium carbonate, calcium hydroxide, calcium formate, sand-binder ratio, water-binder ratio and polycarboxylate superplasticizer all can improve the fluidity and compressive strength of the materials within a certain range. When the replacement rate of coal gangue aggregate increases, the tensile elastic modulus and ultimate tensile strength of HDCRRM material decrease, while the ultimate tensile strain increases. When the replacement rate of coal gangue aggregate is 100 %, the compressive strength of HDCRRM is 40.5 MPa, the ultimate tensile strain is 2.83 %, and the average crack width is 50.27μm. The early compressive strength of HDCRRM is mainly provided by a large amount of ettringite and C-S-H gel.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call