Experimental Study On Dynamic Mechanical Properties Of Geopolymer Concrete

Geopolymer concrete(GPC)is one of the most active inorganic polymer materials in recent years.It has the advantages of good performance,wide source of raw materials,simple process,low energy consumption and low environmental pollution,so it is a kind of green environmental protection material for sustainable development.It has been gradually used in civil engineering,traffic engineering and other fields.In the past,the research on geopolymer concrete is mostly limited to the material properties under quasistatic loading,only under uniaxial compression,splitting tension and bending loading.The research on the impact characteristics and dynamic mechanical properties of geopolymer concrete is very limited.However,building structures are likely to be subjected to dynamic loads during their design life,such as earthquake,high-speed impact load or explosion load,and the response of engineering materials and structures under impact load is obviously different from that under quasi-static load,so it is very necessary to understand the characteristics of materials under high strain rate.This paper mainly focuses on the experimental study on the dynamic mechanical properties of high strength and ordinary strength geopolymer concrete.(1)Firstly,this paper explains the preparation method and processing method of geopolymer concrete selected in this test.it also explains the test equipment needed for dynamic mechanical test,the test principle and the calculation method of material strength and strain rate of different dynamic mechanical properties test.(2)The compressive strength of geopolymer concrete with different strength under quasi-static pressure load is studied.(3)The dynamic impact compression test is carried out by using split Hopkinson bar,the failure patterns under different strain rates are obtained,and the empirical formula of dynamic compressive strength magnification factor of geopolymer concrete with different strength is given.As for the dynamic tensile properties of geopolymer concrete,the splitting test of geopolymer concrete with different strengths under quasi-static loading was carried out first,and the quasi-static splitting tensile strength of geopolymer concrete was obtained.Then the failure modes of geopolymer concrete under different strain rates are obtained by Instron dynamic splitting test and Hopkinson dynamic spallation test respectively.The empirical formulas of dynamic tensile strength and dynamic increase factor of geopolymer concrete under the two test methods are obtained,and the two experimental results are compared and analyzed.In this paper,through the above experimental study on the dynamic mechanical properties of geopolymer concrete with different strength,the dynamic failure mode of the material,the strain rate effect under high strain rate and the stress-strain relationship are analyzed.the purpose of this paper is to provide a certain theoretical basis for the application of geopolymer concrete to the explosion-proof members of building structures and the numerical simulation of the dynamic mechanical properties of such members in the future.