UHPC-NC刻槽界面剪切性能及抗剪强度计算方法

Shear Properties and Shear Strength Calculation Method of UHPC-NC Grooved Interface

摘要:

考虑普通混凝土（NC）强度等级、刻槽密度2个因素，通过斜剪试验和双面直剪试验，分析了超高性能混凝土-普通混凝土（UHPC-NC）刻槽界面在压剪和纯剪应力状态下的剪切性能，并基于试验结果给出了UHPC-NC刻槽界面抗剪强度计算公式以及此类界面斜剪试件的界面倾角范围.结果表明：界面倾角30°斜剪试件表现为NC压溃破坏或界面剪切+NC压溃组合破坏，界面倾角60°斜剪试件和直剪试件均表现为界面剪切破坏；试件强度与NC强度成正比，随着刻槽密度的增大，界面倾角30°斜剪试件的强度基本不变，界面倾角60°斜剪试件和直剪试件的强度逐渐增大；UHPC-NC刻槽界面的抗剪内摩擦角取决于NC强度等级.

Abstract:

Considering the two factors of normal concrete （NC） strength and groove density， the shear properties of the UHPC-NC grooved interface under compressive shear and pure shear stress states were analyzed by oblique shear test and double-sided shear test. Based on the test results， a formula for calculating the shear strength of the UHPC-NC grooved interface was proposed， along with the range of interface inclination angles for oblique shear specimens of such interfaces.The results show that the oblique shear specimen with an interface inclination angle of 30° exhibits NC compression damage or interfacial shear plus NC compression damage， while those with an interface inclination angle of 60° and direct shear specimens exhibit interfacial shear damage. The ultimate strength of specimens increases with the increase of NC strength. With the increase of groove density， the ultimate strength of inclined shear specimen with an interface angle of 30° remains basically unchanged， and the ultimate strength of inclined shear specimen with an interface angle of 60° and straight shear specimen gradually increases. The shear internal friction angle of the UHPC-NC grooved interface depends on the NC strength grade.