Experimental Study On The Durability Of Glazed Hollow Beads Thermal Insulation Mortar Under Carbonization Effect

Glazed hollow beads (GHB) thermal insulation mortar is a type ofinorganic insulation materials meeting the energy demand in China. Itsdurability performance has an important influence on the insulation effect andservice life of insulation system. However,its durability and service life couldnot accurately be assessed by the weathering test methods based on organicinsulation system.Therefore, to explore the test and evaluation methodsapplicable to inorganic insulation system has important theoretical and practicalsignificance.As a part of NSFC project,the carbonation effect on GHB insulationsystem was experimentally studied.The anti-carbonation of GHB insulationmortar and the effect that carbonation post on the frost resistance of thermalinsulation mortar are studied in this paper on the basis of existing researchresults, combining with the features of thermal insulation mortar and taking a combination of macro and micro methods. Specific studies are as follows:1. The experimental study on the anti-carbonation properties of insulationmortar.The accelerated carbonation experiments of GHB thermal insulationmortar has been conducted by designing three kinds of thermal insulationsystems and selecting0,3d,7d,14d,28d five kinds of parameters. And theanalysis of the carbonation product using X-ray diffraction and scanningelectron microscopy experiments has been determined. Meanwhile, compare thethe laboratory test data with the field measurement data, to verify the expressionrelationship between accelerated carbonization and natural carbonation. Testresults have showed that the pores inside the mortar was been filled withcarbonized product making lower porosity;The carbonation depth of thermalinsulation mortar increases with ages close to a power function relationship. Thecarbonation depth prediction model has been established using the regressionanalysis method.2. The experimental study on the basic performance of thermal insulationmortar under the carbonation.The basic physical and mechanical properties testsof thermal insulation mortar after0,7d,14d,28d different carbonization ages havebeen conducted.Test results have showed that the linear expansion coefficient ofthermal insulation mortar reduced24.44%,and the thermal conductivityincreased8.73%. And the elastic modulus, cube compressive strength, crimpingratio, tensile strength and tensile bond strength are enhanced to a certain extent,significantly greater increased in pre-carbonization. The growth rate are16.58%, 33.12%,11.70%,55.71%,14.41%.3. The experimental study on the on frost resistance performance of thermalinsulation mortar under the carbonation.The0,15,25,50times freeze-thaw cyclestest of thermal insulation mortar after0,7d,14d different carbonization ages havebeen conducted.Then determine the mass loss and the relative dynamic elasticmodulus to analyze the impact that carbonation on frost resistance. Test resultshave showed that the mass loss rate and relative dynamic elastic modulus lossrate of thermal insulation mortar after carbonization is smaller thannon-carbonized, and the maximum loss rates are reduced by18.51%,13.93%. Itcan prove that carbonation can increase frost resistance of mortar to a certainextent.4. The experimental study on the basic performance of thermal insulationmortar under the carbonation thaw coupling effect.The basic physical andmechanical properties tests of thermal insulation mortar after different coupledeffect have been conducted. Test results have showed that the thermalconductivity increased13.09%.And the reduction rate of elastic modulus, cubecompressive strength, crimping ratio, tensile strength and tensile bond strengthdecreased. It can prove that the longer the carbonization time, the stronger frostresistance, within a reasonable period of carbonation age range.The conclusions obtained from above tests will provide experiment basisfor durability design and life prediction of GHB thermal insulation mortarsystem.