Study On The Lightweight Preparation And Performance Of Autoclaved Silicate Aggregate

Aiming at the problem of high density of non-sintered ceramsite,this subject proposes a method for preparing lightweight non-fired ceramsite using weight-reducing materials,and around the light-weight non-fired ceramsite,the mechanical properties and thermal insulation properties of lightweight aggregate concrete are developed.Research on internal curing performance and expansion performance of sulfur-containing light aggregate.Prepared lightweight non-sintering silicate lightweight aggregate.Using floating beads,expanded perlite particles,expanded perlite powder,fly ash and cement as raw materials,using the absolute volume method to design lightweight aggregates,3 types were prepared under the conditions of 1MPa,180℃hydrothermal synthesis for 8 hours Lightweight aggregates:Floating beads silicate aggregates(FBSAs),Expanded perlite granule silicate aggregates(EPGSAs),expanded perlite powder silicate aggregates Materials(Expanded perlite powder silicate aggregates,EPPSAs).The basic properties of three kinds of lightweight aggregates are characterized respectively:bulk density,apparent density,water absorption and cylinder compressive strength.The experimental results show that under the condition of ensuring the forming ability of lightweight aggregates,the weight-reducing material can be increased to50vol.%,and with the incorporation of weight-reducing materials,the density of the non-fired ceramsite is significantly reduced.When the weight-reducing material content increased from10vol.%to 50vol.%,the apparent density of FBSAs decreased from 1779 kg/m~3 to 1090 kg/m~3,and the apparent density of EPGSAs decreased from 1654 kg/m~3 to 1188 kg/m~3.The apparent density of EPPSAs decreased from 1796 kg/m~3 to 1406 kg/m~3.The mechanical properties and thermal insulation properties of lightweight aggregate concrete with different densities are explored.By configuring concrete with two different types of non-fired silicate lightweight aggregates and measuring the thermal conductivity,the thermal conductivity of the concrete is between 0.63 w/(m·k)-0.98 w/(m·k),which is much lower It is1.74 w/(m·k)on ordinary concrete.Lightweight aggregates can significantly reduce the thermal conductivity of concrete.The larger the volume of lightweight aggregates,the lower the thermal conductivity of lightweight aggregate concrete.Through the experiments of crushed stone and light aggregate intermixing,ceramic sand and sand intermixing experiments,it can be known that the light aggregate plays a certain role in promoting cement hydration in the internal curing of concrete,thereby enhancing the overall mechanical properties of concrete.This"internal curing"effect of enhancing the compressive strength of concrete can be demonstrated in lightweight aggregate concrete prepared from high-strength lightweight aggregates(≥22MPa),but in lightweight aggregate concrete with lower cylindrical compressive strength,internal curing The effect cannot make up for the lack of strength,and the strength of concrete is reduced due to insufficient support of aggregate.Prepared high-sulfur slag light aggregate and explored the expansion properties of high-sulfur slag light aggregate concrete.The results show that the strength of aluminate high-sulfur slag light aggregate increases with the increase of aluminate cement content,but it is generally lower than that of silicate high-sulfur slag light aggregate.The swelling caused by the formation of ettringite mainly occurred in the first 14 days,and the light aggregate with a sulfur content of less than 6.5%has no silicon-alkali reaction harm.Lightweight silicate high-sulfur slag aggregate has a better ability to resist expansion,and when used in concrete,it does not have expansion hazards.Experiments show that it is technically feasible to release the expansion source in advance by prefabricating lightweight aggregates to reduce the harm of high-sulfur slag to concrete.