Experimental Study On ECC Mechanical Properties Of Hybrid Fibers Containing Ceramic Waste Under Different Curing Conditions

Engineered cement Composite(ECC),which was Engineered to achieve more than 3%ultimate tensile strain in a single axial tensile test,has been more and more recognized by the industry,but was less widely used due to its high cost and slow strength increase.With the continuous improvement of the level and output of China's ceramic industry,the amount of ceramic waste is also increasing day by day.As a large number of industrial wastes such as fly ash are used in ECC,it leads to the consideration of whether ceramic wastes can be used in ECC.In this paper,ceramic waste and basalt fiber are introduced into the research and preparation of ECC,and their basic mechanical properties are discussed through cubic compressive test,axial compressive test and uniaxial tensile test.The main work of this paper is as follows:(1)In this paper,particle size distribution,micro-morphology and pozzolanic activity of ceramic waste were tested and studied by means of particle size detection,microscopic detection and activity index test.In the activity index test,mineral admixtures such as fly ash,ceramic powder and slag were used to replace the cement in the cement mortar with a ratio of30% and 50% respectively,and the flexion strength and compressive strength of the materials on day 7 and day 28 were tested to obtain the activity index.The results show that the early activity of ceramic powder is not as good as fly ash,but the activity index grows faster than fly ash in the late stage,and the fineness of ceramic powder is higher than fly ash.(2)Compressive performance tests and microstructure analysis were conducted on ECC substrates containing ceramic wastes under standard curing and thermal curing.Through the analysis and comparison of test data and microstructure,the influence relationship between standard curing and thermal curing on the strength and microstructure of ECC matrix was revealed.(3)Through the axis of cube compressive strength test,compression test and uniaxial tensile test,the standard curing hybrid fiber containing ceramic waste ECC basic mechanical properties are studied,analysis the ceramic waste and basic relationship between the mechanical properties of basalt fiber on ECC,and presents a ceramic waste and basalt fiber dosage of appropriate Suggestions.The results show that the axial compressive strength,initial tensile crack strength,ultimate tensile strength,compression and tensile elastic modulus of ECC matrix are effectively increased with the increase of the content of ceramic powder,but the ultimate compression and tensile strain decrease to different degrees.When the content of ceramic powder is greater than 35%,the comprehensive improvement effect of ECC is the same as that of 35%.It is recommended that the content should not exceed 35%.The increase of the content of ceramic sand improves the compressive deformation capacity of ECC,but has little influence on its compressive strength.The influence of ceramic sand on the tensile property of ECC is that with the increase of the content,the relationship between the decrease first and the increase later appears.With the decrease of PVA fiber and the increase of basalt fiber,the cubic compressive strength of ECC decreased by 2.1% and 10.6%,respectively,and the tensile strength of ECC was greatly improved in each group.However,when PVA fiber was reduced to 1% of the volume content,IT was difficult for ECC to play a good strain hardening characteristics.(4)Compared and analyzed the high-temperature thermal curing and standard curing conditions,as well as the cubic compressive strength,axial compressive performance,uniaxial tensile performance and shrinkage deformation performance of ECC,to obtain the relationship between the mechanical properties of ECC at different curing temperatures and times,and to provide the optimal curing temperature and time.It was found that the compressive strength of ECC was slightly higher than that of the standard curing at day 28,while the compressive and tensile properties of ECC did not change much when the thermal curing time was increased to day 7.ECC cured at 50? is more stable than that at 70?.(5)For P0-B1,P1-B1 and P1S1-B1 ECC of three groups of mixture ratio under the condition of high temperature curing and standard curing shrinkage deformation test,the test results show that high temperature thermal curing and the addition of ceramic powder can effectively reduce the ECC under the condition of natural drying shrinkage deformation,P0-B1 group,P1-B1 and P1S1-B1 group of contraction deformation test results showed: under the standard curing condition,the growth rate of contraction deformation value of the ECC and size are higher than that of high temperature curing.When the age increases gradually,the shrinkage deformation values of P0-B1 and P1S1-B1 change consistently.Due to the interaction of ceramic powder and ceramic sand,the internal porosity of ECC is small,and the shrinkage deformation of P1S1-B1 group under the condition of high-temperature curing is also minimum.