Study On Mechanical And Piezoresistance Of High-Performance Concrete With Ceramic Tile Powder/Ceramic Tile Aggregate In Acid Rain Environment

With the continuous advancement of global industrialization,a large amount of solid wastes are produced in the process of industrial production.,and one of the current issues is converting solid waste into useable resources.Ceramic waste tiles,as one of the solid wastes,have a hard texture and a rough surface,and finely ground waste tile powder has potential pozzolanic activity.These characteristics make it possible for ceramic waste tiles to partially replace cement and natural sand and gravel aggregates.Therefore,in this paper,the ceramic waste tile powder and ceramic tile particles after crushing and grinding are used as mineral admixtures and recycled fine aggregate to produce high-performance recycled concrete of ceramic waste tile.The influence rule and mechanism of mechanical and piezoresistance under different acid rain environment are investigated.The main research contents and achievements of this paper are as follows:（1）The mechanical properties and mechanism of high-performance concrete with ceramic waste tile powder/ceramic tile aggregate under simulated acid rain erosion were investigated.The influences of ceramic waste tile powder content,corrosion time,p H value and SO₄^2-ion concentration of acid rain solution on the appearance,mass loss,flexural strength,compressive strength,fracture toughness and other indexes of high-performance concrete with ceramic waste tile powder/ceramic tile aggregate were tested.The results show that with the increase of corrosion time,the appearance color of high-performance concrete with ceramic waste tile powder/tile aggregate shows a tendency of black-gray-tan-off-white,and the addition of 55%ceramic waste tile powder can reduce the surface damage and mass loss of concrete.With the increase of corrosion time,the compressive strength,flexural strength and fracture toughness of high-performance concrete with ceramic waste tile powder/ceramic tile aggregate increased first and then decreased High performance concrete with large amount of ceramic waste tile powder/ceramic tile aggregate still maintain relatively higher flexural strength,compressive strength and corrosion resistance coefficient after acid rain corrosion.The fracture energy of high-performance concrete with ceramic waste tile powder/ceramic tile aggregate decreases with the decrease of p H value.25%ceramic waste tile powder improve the fracture toughness of high-performance concrete under severe acid rain environment.The microcosmic analysis shows that,carbonization,H⁺dissolution corrosion and sulfate corrosion act on concrete under the acid rain corrosion environment.Under high concentration SO₄^2-ionic acid rain corrosion environment,the addition of ceramic waste tile powder effectively reduces the volume and quantity of gypsum.The ITZ width of high-performance concrete is reduced by the addition of 40%ceramic tile powder.The improvement effect of ceramic waste tile powder on the overall microstructure of high-performance concrete is more attributed to the filling effect of micro-particles.The influence degree of factors on the corrosion resistance of high-performance concrete is obtained through the analysis of grey correlation degree,which is in descending order:p H value of acid rain,corrosion time,ceramic waste tile powder content and SO₄^2-ion concentration.（2）The DC resistivity and AC resistivity of high-performance concrete with ceramic waste tile powder/ceramic tile aggregate under different conditions were tested.The piezoresistivity test was carried out on the high-performance concrete with ceramic waste tile powder/ceramic tile aggregate under acid rain environment,and the relationship between the fractional change in electrical resistivity（FCR）of the high-performance concrete and the compressive stress and compressive strain under the elastic stage and compression failure load was investigated.The influences of ceramic waste tile powder content,loading amplitude,loading rate and failure load on the piezoresistivity of high-performance concrete were analyzed.The results show that the DC and AC resistivity of high-performance concrete increases with the increase of ceramic waste tile powder content.The high-performance concrete with 55%ceramic tile powder has the maximum DC resistivity and AC resistivity under different corrosion conditions.The DC and AC resistivity of ceramic waste tile powder high performance concrete is more significantly affected by acid rain H⁺concentration,but less affected by SO₄^2-concentration.In three different acid rain corrosion environments,the effect of ceramic waste tile powder content on the piezoresistivity of high-performance concrete is different.Although the FCR of high-performance concrete with high content of ceramic waste tile powder is low,it has good piezoresistivity stability.The strain sensitivity of high-performance concrete with 40%ceramic waste tile powder does not exceed±1.38 under different corrosion environment.The FCR,stress sensitivity and strain sensitivity of each group decreased with the increase of loading rate,but increased with the increase of loading amplitude.Under compression failure load condition,the addition of ceramic waste tile powder improves the piezoresistivity of high-performance concrete after corrosion.25%and 40%ceramic tile powder still have better piezoresistivity after corrosion by severe acid rain,and their strain sensitivity is increased by 40.3%and 56.7%compared with control group,respectively.