Experimental Study On Mechanical Properties Of Grout And Bond Behavior Between Steel Bar And Grout

With the vigorous development of the prefabricated building,as an important anchoring material to connect the prefabricated component,grout is widely used in the sleeve grouting connection and the grouting anchor lap connection.Compressive strength is an important indicator to characterize the performance of grout.However,the test methods for determining the compressive strength of grout are different at home and abroad,and the measured compressive strength cannot be directly used for reference.Compared with concrete,the material composition of grout does not include coarse aggregate.Whether the mechanical properties and bond behavior are equivalent to the mechanical properties and bond behavior of concrete,and whether the influence of various factors on the bond behavior of the grout is consistent with the results of concrete research,these problems need to be studied.This paper mainly includes the following three aspects of research:(1)According to the test method in the domestic grout standar d,the compressive strength of the grout is determined.Then the grout is regarded as a kind of “special concrete”.According to the domestic concrete standard,various mechanical properties of the grout are determined,including cubic compressive strength,axial compressive strength,static modulus of elasticity and splitting tensile strength.The conversion relationship between the mechanical properties of the grout according to the concrete standard and the compressive strength measured by the grout stan dard is established.(2)According to the different standards for determining the compressive strength of grout at home and abroad,the strength specimens of the specified shape and size shall be produced,and the loading system specified by the standard s hall be used to determine the compressive strength of grout in various countries including China/Japan/Europe,the United States,Malaysia and Australia/New Zealand.Compare and analyze failure mode and compressive strength values of four kinds of specimen s with different shape and size,and establish a conversion relationship between compressive strength values.(3)18 sets of 90 specimens of pull-out test were produced,and the bond behavior of steel bars embedded in grout was tested by pull-out test.The effects of grout strength,steel bar surface shape,steel bar diameter,embedment length,stirrup length and spacing on the bond behavior of steel bars embedded in grout were discussed,including failure mode,bond-slip curve and the characteristic value of bond behavior.In addition,the difference in bond behavior between grout and ordinary concrete was compared and analyzed.