Experimental Study On Dynamic Cracking Performance Of Cement Mortar After Grouting Reinforcement

With the rapid development of society,there is more and more demand for concrete construction.However,one of the most common quality problems in concrete construction is concrete cracks,this damages the stability and durability of the building and reduces its service life.Nowadays,there are more and more methods to repair concrete cracks,and the grouting reinforcement is widely used in bridges,houses,highways and other fields because of its high efficiency,economy and simple construction.Therefore,it is very important to study the mechanical properties and deformation failure test of ordinary cement mortar and grout reinforced cement mortar.In this paper,the mechanical,deformation,failure and energy dissipation characteristics of grout-reinforced cement mortar specimens with different crack sizes and different impact velocities are studied in detail.The conclusions are as follows:(1)The tensile strength and elastic modulus of ordinary cement mortar are obviously higher than those of reconstituted cement mortar.(2)under the impact load of high strain rate and at the same impact angle,the grouting strength of 3mm cracks is obviously higher than that of 5mm cracks.The strength of grout reinforced cement mortar changes with the increase of Impact Angle(0°～90°),and the whole law first decreases(0°～45°),then increases(45°～90°)and then decreases(90°～120°).(3)the elastic modulus of grout reinforced cement mortar is closely related to the impact angle,and the change law is the same as the dynamic tensile strength law of cement mortar,and there is a critical angle in the impact angle to minimize the elastic modulus of the sample.(4)under the impact pressure of 0.3 MPA,the strength of the grouted and reinforced cement mortar is increased to 0.3 MPA,and the strength of the grouted and reinforced cement mortar is increased to 0.5 MPA,and the strength of the grouted and reinforced cement mortar is increased to 0.5 MPA,and the strength of the grouted atmosphere is increased There are three types of fracture forms of grout reinforcement mortar caused by different impact angles:①,Slip Fracture(0°)along the grout surface of grout reinforcement mortar;②,along the Impact Angle crack damage and along the grouting surface slip damage at the same time the broken shape(30°,45°,60°,120°),③,through the grouting surface crack damage(90°)and ordinary cement mortar failure mode is the same;(5)the crack size of grouting reinforced cement mortar has an effect on the absorption energy:The absorption energy rate of ordinary cement mortar is higher than that of 3mm grouting reinforced cement mortar and 5mm grouting reinforced cement mortar,the absorption rate of 3mm grouting reinforced cement mortar is higher than that of 5mm grouting reinforced cement mortar in every impact angle.The impact angle has an effect on the absorption rate of the Specimen:When the impact angle is 90°,the absorption rate of grout reinforced cement mortar is the most similar to that of ordinary cement mortar,the energy absorption rate decreases with the Impact Angle(0°～45°)and increases with the impact angle(45°～90°),and the overall curve of the Impact Angle(0°～90°)is approximately u-shaped.Figure[19]table[13]reference[71]...