The reflected optical caustics method is applied to study dynamic fracture problems in hardened cement paste. First both the unreinforced cement paste and the glass fibres reinforced cement paste specimens were fabric...The reflected optical caustics method is applied to study dynamic fracture problems in hardened cement paste. First both the unreinforced cement paste and the glass fibres reinforced cement paste specimens were fabricated and the reflective coating on the surface of the specimen was prepared. Secondly the crack path and the shadow spot patterns during the crack propagation process for the two specimens were recorded by using a multi-spark high speed camera.Thirdly some dynamic parameters of two cement paste specimens including crack onset time the dynamic stress intensity factor and crack growth velocity were determined and analyzed comparatively.This indicates that the glass fibres can improve the fracture resistance and delay fracture time.These results will play an important role in evaluating the dynamic fracture properties of cement paste.展开更多
Coal waste(CW)could be used for soil stabilization due to the pozzolanic elements it contains.There hasn’t been much investigation into how different fibers affect the mechanical qualities of stabilized sand,although...Coal waste(CW)could be used for soil stabilization due to the pozzolanic elements it contains.There hasn’t been much investigation into how different fibers affect the mechanical qualities of stabilized sand,although adding fibers of any kind to soils may improve the soil because of fiber characteristics like rigidity.For this reason,several tests were carried out on sand that contained 6%cement(by dry weight of used sand),5 wt%CW,0 wt%,0.25 wt%,and 0.50 wt%fiber,as well as the unconfined compressive strength(UCS)test,indirect tensile strength(ITS)test,unconsolidated undrained(UU)triaxial test,scanning electron microscope(SEM)test and ultrasonic pulse velocity(UPV)test.The results showed that in comparison to other fiber reinforced mix designs,the specimen reinforced with 0.5%fibers and the mix design of 0.25 wt%glass and 0.25 wt%polypropylene(PP)fibers exhibited the maximum strength.Examining the impact of fiber type found that glass fibers influence PP strength more favorably than other fiber types.The use of PP fibers is an excellent solution for the problem of large strains in design processes,while adding glass fibers is considered a suitable treatment for issues related to small strains.展开更多
基金The Ph.D.Programs Foundation of Ministry of Education of China(No.20120023120020)the National Natural Science Foundation of China(No.51404273)
文摘The reflected optical caustics method is applied to study dynamic fracture problems in hardened cement paste. First both the unreinforced cement paste and the glass fibres reinforced cement paste specimens were fabricated and the reflective coating on the surface of the specimen was prepared. Secondly the crack path and the shadow spot patterns during the crack propagation process for the two specimens were recorded by using a multi-spark high speed camera.Thirdly some dynamic parameters of two cement paste specimens including crack onset time the dynamic stress intensity factor and crack growth velocity were determined and analyzed comparatively.This indicates that the glass fibres can improve the fracture resistance and delay fracture time.These results will play an important role in evaluating the dynamic fracture properties of cement paste.
文摘Coal waste(CW)could be used for soil stabilization due to the pozzolanic elements it contains.There hasn’t been much investigation into how different fibers affect the mechanical qualities of stabilized sand,although adding fibers of any kind to soils may improve the soil because of fiber characteristics like rigidity.For this reason,several tests were carried out on sand that contained 6%cement(by dry weight of used sand),5 wt%CW,0 wt%,0.25 wt%,and 0.50 wt%fiber,as well as the unconfined compressive strength(UCS)test,indirect tensile strength(ITS)test,unconsolidated undrained(UU)triaxial test,scanning electron microscope(SEM)test and ultrasonic pulse velocity(UPV)test.The results showed that in comparison to other fiber reinforced mix designs,the specimen reinforced with 0.5%fibers and the mix design of 0.25 wt%glass and 0.25 wt%polypropylene(PP)fibers exhibited the maximum strength.Examining the impact of fiber type found that glass fibers influence PP strength more favorably than other fiber types.The use of PP fibers is an excellent solution for the problem of large strains in design processes,while adding glass fibers is considered a suitable treatment for issues related to small strains.
