Drying Shrinkage And Autogenous Shrinkage Experimental Research Of High Performance Concrete

With the increased use of high performance concrete(HPC) in building structures, it is becoming more and more significant to further the studies on the autogenous shrinkage and the drying shrinkage of HPC. The paper describes the research studies on the relationship between the quantity and the varieties of mineral admixture and the autogenous shrinkage and the drying shrinkage of HPC. The main achievements can be summarized as follows: 1. The paper proceed five group autogenous shrinkage experiments on the HPC(including only flying ash in the HPC, both flying ash and metakaolin in the HPC, both flying ash and slag in the HPC), with the improved autogenous shrinkage experimental device. After considering the influence of temperature strain of concrete, it is drawn out that a more precise conclusion between the quantity and the varieties of mineral admixture and the autogenous shrinkage of HPC. 2.The paper proceed five group autogenous shrinkage experiments on the HPC(including only flying ash in the HPC, both flying ash and metakaolin in the HPC, both flying ash and slag in the HPC) with the improved drying shrinkage experimental device. It is drawn out that a more precise conclusion between the quantity and the varieties of mineral admixture and the drying shrinkage of HPC after experiments. Then, a comparison between the drying shrinkage of HPC and autogenous shrinkage of HPC in the third day and the fourteenth day is carried out. 3.With the help of scanning electron microscopy, different site(interface zone, cement paste etc.) in the HPC is scanned. It is analyzed that how the quantity and the varieties of mineral admixture and the age of concrete influence the microscopy morphology of HPC. Then, it is researched that the relationship between the change in the scanning electron microscopy picture and the autogenous shrinkage and the drying shrinkage of HPC. 4.After the X-ray diffraction experiment, it can be drawn out that the X-ray diffraction chart of HPC powder with different quantity of flying ash and slag and different age of concrete. Then, it is researched that the relationship between the change in the X-ray diffraction chart and the autogenous shrinkage and the drying shrinkage of HPC. 5.It is compared that the veracity in forecasting the shrinkage of HPC with three shrinkage calculation models in this paper. Then, combined the drying shrinkage experimental result in this paper, and considering the influence of the shrinkage of HPC by the varieties and the quantity of flying ash and the quantity of slag, a shrinkage calculation model of HPC is brought forward. It can enhance the veracity in forecasting the shrinkage of HPC with the model.