The grout-rock interfacial property is one of the key factors associated with the strength of grouted rock masses.In this study,direct shear tests and nanoindentation tests were adopted to investigate the mechanical p...The grout-rock interfacial property is one of the key factors associated with the strength of grouted rock masses.In this study,direct shear tests and nanoindentation tests were adopted to investigate the mechanical properties of the grout-rock interface at both the macroscale and microscale.The cohesion of the cement specimens was higher than that of the grout-infilled joint specimens,while their internal friction angle was lower than that of the grout-infilled joint specimens.A“separation method”for identifying the different phases according to the qualitative and quantitative estimations was introduced,and the irregular interfacial transition zone(ITZ)thickness and elastic modulus were estimated.The ITZ thickness of the grout-infilled sandstone specimen ranged from 0 to 30μm,whereas it was within the range of 10-40μm for the grout-infilled mudstone specimen.The average elastic modulus of the ITZ in grout-infilled sandstone and mudstone specimens was approximately 58.2%and 54.1%lower than that of the bulk grout,respectively.Regarding the incidence of the rock type,the interlacing between the grout and sandstone was better developed.The ITZ with a higher porosity and lower modulus had a significant effect on the mechanical properties of the grout-infilled specimens.展开更多
Geopolymer composites containing woven cotton fabric(0-8.3 wt%)were fabricated using the hand lay-up technique,and were exposed to elevated temperatures of 200℃,400℃,600℃,800℃and 1000℃.With an increase in tempera...Geopolymer composites containing woven cotton fabric(0-8.3 wt%)were fabricated using the hand lay-up technique,and were exposed to elevated temperatures of 200℃,400℃,600℃,800℃and 1000℃.With an increase in temperature,the geopolymer composites exhibited a reduction in compressive strength,flexural strength and fracture toughness.When heated above 600℃,the composites exhibited a significant reduction in mechanical properties.They also exhibited brittle behavior due to severe degradation of cotton fibres and the creation of additional porosity in the composites.Microstructural images verified the existence of voids and small channels in the composites due to fibre degradation.展开更多
基金Project(52004144)supported by the National Natural Science Foundation of ChinaProject supported by the Shandong Province Higher Educational Young Innovative Talent Introduction and Cultivation Team,China。
文摘The grout-rock interfacial property is one of the key factors associated with the strength of grouted rock masses.In this study,direct shear tests and nanoindentation tests were adopted to investigate the mechanical properties of the grout-rock interface at both the macroscale and microscale.The cohesion of the cement specimens was higher than that of the grout-infilled joint specimens,while their internal friction angle was lower than that of the grout-infilled joint specimens.A“separation method”for identifying the different phases according to the qualitative and quantitative estimations was introduced,and the irregular interfacial transition zone(ITZ)thickness and elastic modulus were estimated.The ITZ thickness of the grout-infilled sandstone specimen ranged from 0 to 30μm,whereas it was within the range of 10-40μm for the grout-infilled mudstone specimen.The average elastic modulus of the ITZ in grout-infilled sandstone and mudstone specimens was approximately 58.2%and 54.1%lower than that of the bulk grout,respectively.Regarding the incidence of the rock type,the interlacing between the grout and sandstone was better developed.The ITZ with a higher porosity and lower modulus had a significant effect on the mechanical properties of the grout-infilled specimens.
文摘Geopolymer composites containing woven cotton fabric(0-8.3 wt%)were fabricated using the hand lay-up technique,and were exposed to elevated temperatures of 200℃,400℃,600℃,800℃and 1000℃.With an increase in temperature,the geopolymer composites exhibited a reduction in compressive strength,flexural strength and fracture toughness.When heated above 600℃,the composites exhibited a significant reduction in mechanical properties.They also exhibited brittle behavior due to severe degradation of cotton fibres and the creation of additional porosity in the composites.Microstructural images verified the existence of voids and small channels in the composites due to fibre degradation.
