Monitoring Of Hydration Process Of Sulphoaluminate Cement Based On Piezoelectric Active Monitoring Technology

The calcium sulphoaluminate cement has been widely used in the rush-repair work,the low-temperature construction and the coastal engineering projects.Its hydration process,especially the strength development of the early stage,determines the various properties of cement after setting and hardening.The research on the physical and mechanical properties of hydration process and the study of the evolution law have important engineering significance.However,there is no better automatic monitoring method for the early hydration of the calcium sulphoaluminate cement;it is essential to develop a detection approach with accuracy and simplicity to monitor and study its early hydration and strength development.As a new smart monitoring technology,piezoelectric active monitoring method has the advantages of fast response rate,linear correlation,and suitable for real-time monitoring.In this study,the method was used to design and fabricate a new type of piezoelectric active monitoring sensor,which was applied to the automatic monitoring of the hydration process of the calcium sulphoaluminate cement.The characteristic of the hydration was analyzed,and the high correlation was found between the energy curve of the piezoelectric signal and the material's property.The mixture of calcium sulphoaluminate cement and ordinary Portland cement is the efficient way to obtain high early strength and the stable performance after setting.A novel smart monitoring box has been invented to monitor the hydration of the composite cement in different mixture ratio.The research proved that the active piezoelectric method could be utilized to conveniently monitor the hydration of cement materials by analyzing the piezoelectric signal.Also,it was found that the inflection point at the curve went up corresponding to the initial setting of the cement.Moreover,it can also predict the compressive strength of the cement material with which it may have a broad application prospect.The experiments of the mixture of calcium sulphoaluminate cement and Portland cement were conducted in this research based on piezoelectric active monitoring method.Combined with some conventional measurement approaches,it was found that the ratio of the calcium sulphoaluminate cement mixture has a significant influence on the performance of the composite cement paste.The certain proportion of calcium sulphoaluminate cement can accelerate the hydration rate at the early stage of the composite cement paste,reduce the influence caused by low temperature to the hydration.When the mixture rate of calcium sulphoaluminate cement was less than 60%,the initial setting time shortened apparently,while the early compressive strength of composite cement mortar decreased in some extent,in conclusion,the calcium sulphoaluminate cement and Portland cement cannot be mixed randomly in particular.