Research On Adiabatic Temperature Rise Experiment And Early Age Cracking Sensitivity Of High-Volume Fly Ash Dam Concrete

Gezhouba group test co.,LTD and Zhejiang University of Technology highvolume fly ash concrete has carried on the systematic study,found that when the dosage of fly ash as high as 80%,from the preparation of low water-binder ratio high-volume fly ash concrete variety of conventional mechanical index still can satisfy the requirement of hydraulic engineering,this can be a normal high-volume fly ash concrete dams in our country the research and application of experimental base,has important practical significance.Therefore,according to the concrete mix ratio provided by Gezhouba dam,this paper prepared the high-volume fly ash concrete with a fly ash content of 80% and the reference fly ash concrete with a fly ash content of 35%,and studied the development law of adiabatic temperature rise,temperature history curve and early cracking sensitivity of high-volume fly ash dam concrete.The research is as follows:1.Adiabatic and semi-adiabatic test methods were adopted to conduct the adiabatic temperature rise test study of the reference concrete and the high-volume fly ash dam concrete.The exothermic law of two kinds of dam concrete during hydration was analyzed.Based on the results of adiabatic temperature rise test,an adiabatic temperature rise model suitable for simulation of concrete temperature field in highvolume fly ash dam was proposed.2.The proposed double exponential adiabatic temperature rise model was substituted into the program for the simulation analysis of dam temperature field.It was found that the incremental form of adiabatic temperature rise model can better simulate the temperature field than the partial derivative form.The temperature history curve of high-volume fly ash concrete obtained by temperature field simulation was analyzed.The temperature history curve can be used in the temperature-stress test under the temperature-matching curing mode of high fly ash concrete.3.Through the temperature stress test of TSTM adiabatic curing mode and matching curing mode for two kinds of concrete,the sensitivity analysis of early cracking of high content fly ash dam concrete was carried out.The time-varying thermal expansion coefficient and its model were obtained through TSTM test,and the timevarying model of thermal expansion coefficient was verified by COMSOL software,providing research basis for the assessment of early cracking sensitivity of mass concrete.