Research On Seismic Performance Of Fabricated Phosphogypsum-concrete Composite Wallboard

Phosphogypsum(PG)is a by-product of the phosphoric acid industry.The annual global production of PG exceeds 300 million tons.However,only 15% of the production materials are recycled currently.As we all know,raw PG has no gelling and self-hardening properties,but PG dehydrated under certain conditions has strength.Some admixtures are often added to the PG to form a phosphogypsum-based composite cementitious material(PGCM)to increase its strength.PGCM has the advantages of light weight,heat preservation,heat insulation and sound insulation,so it is often used as a new type of wallboard material.However,most of the phosphogypsum composite wallboards have low strength and poor seismic performance,which hinders their large-scale use of engineering practice.This article mainly carried out the following research:(1)The single factor tests were used to study the effects of cement,retarder,water reducer,ash calcium powder,etc.on the compressive strength of dehydrated PG,the X-ray diffraction(XRD)and scanning electron microscopy(SEM)was used to analyses the phase composition of PG and the hydrate of PGCM under various dehydration conditions.At the same time,the effects of dehydration temperature and dehydration time of PG on the compressive and flexural strength of PGCM were analyzed.The optimal mix ratio determined by orthogonal experiment and the influence of each admixture on the mechanical properties of PGCM was analyzed.(2)Through the experimental research on the compressive performance of two size PGCM specimens,the compressive strength reduction coefficient was given in the range of0.6?0.69.The PGCM splitting tensile test shown that the axial compressive strength should be 0.042?0.092 times of the splitting tensile strength.Finally,the measured axial compression and splitting tensile stress-strain curves are fitted through the Origin software,and the correlation coefficient R and the confidence probability F were used as the evaluation criteria of the fitting results to obtain the constitutive relationship.(3)A prefabricated phosphogypsum-concrete composite wallboard(PCCW)finite element model was established through Abaqus finite element software,input three different strengths of PGCM constitutive relationship to PCCW finite element model,and the cooperative performance between PGCM and reinforced concrete frame and seismic performance was analyzed.It is verified that the cooperative work performance between PGCM and reinforced concrete frame is good with a good seismic performance.(4)Based on the software ABAQUS,the thickness and the thickness of the concrete slot of the wallboard model were adjusted to analyze the influence of different wallboard thicknesses and slot thicknesses on the seismic performance of PCCW,and finally the better size of the wallboard was given.