| Ceramic is a common manufacturing material,which has been used for many industrial and technological purposes for a long time,such as pottery and sanitary ware.However,about30% of ceramic products are damaged in the production process,and the annual output of waste ceramics in China is more than 10 million tons.Ceramic wastes have poor biodegradability,and there is no effective recycling method at present.Years of accumulation make the ceramic industry face the pressure of finding solutions.Compared with a large number of research results obtained on macro-scale such as the mix proportions and optimal content of ceramic sand concrete,the research on micro-mechanism such as pore structure of ceramic sand cement-based materials has not received enough attention.The purpose of this paper is to study the pore structure,mechanical properties and durability of ceramic sand cement-based materials through experiments.Using microscopic test to study the influence of ceramic sand on the pore structure of cement-based materials;The evolution law of mechanical properties and durability of ceramic powder cement-based materials was studied by macro-test.Combined with the pore structure parameters measured by micro-test,considering the multi-scale research ideas from micro-structure to macro-material transfer behavior,the long-term performance evolution law of ceramic powder cement-based materials is studied,which provides a research basis for recycling waste ceramics and reducing the structural use cost.In this paper,ceramic is used as fine aggregate to replace quartz sand in cement-based materials from 0% to 100% with 20% gradient,and a group of ceramic sand with the same replacement rate and ceramic as cementing material to replace 20% of cement are added,and experimental comparison is made,with a total of 12 mixing ratios.Mechanical property test,water absorption test,air permeability test,chloride ion penetration test,sulfate attack resistance and other durability tests were carried out on fresh cement mortar specimens,and scanning electron microscope test and mercury injection test were carried out on the specimens.The results indicate that the ultimate compressive strength of ceramic sand cement mortar after 180 days curing is over 95 MPa,and the bending strength is around 9.5MPa.Among them,60% ceramic sand is the best,and its mechanical properties are close to the limit value in each age,and the improvement range is 11.6%～33% compared with the control group.In the durability test,the content of 60% ceramic sand is the inflection point.When the content is lower than this,the water absorption rate,gas permeability and electric flux gradually decrease,while when the content is higher than 60%,the water absorption rate,gas permeability and electric flux increase.In the durability test,the gas permeability and electric flux decrease by 51.6%～67% and 17.8%～31.6% respectively compared with the control group.Scanning electron microscope(SEM)experiment shows that the cracks,pores and cement-mortar Interfacial transition zone(ITZ)on the surface of the specimen are gradually filled with hydration products with the increase of curing time,and the specimen becomes denser.Mercury injection experiment shows that the addition of ceramic sand reduces the proportion of macropores in the specimen,increases the proportion of mesopores,reduces the average pore size and refines the pore size,which also improves the mechanical properties and durability of the specimen with the increase of curing time. |
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