Study On Properties Of Reactive Magnesium Oxide Carbonized Concrete

The development of the cement industry has been accompanied by problems of high emissions,high energy consumption,and high pollution.In order to reduce the environmental harm of the construction industry,the academic community has been looking for green and low-carbon cement alternatives.Reactive magnesium oxide has become one of the potential cement alternatives due to its high strength,low emissions,low energy consumption,and recyclability.In this paper,the mechanical properties,bonding properties,Frost resistance,micro-mechanism,Variation of carbonation depth of reactive magnesium oxide carbonized concrete are studied through laboratory tests.The main conclusions are as follows:(1)Replace the cement with reactive magnesium oxide with different content(0%,20%,35%,50%),and test the compressive strength,split tensile strength,and elastic modulus of the concrete after carbonization through laboratory tests.The test results show that 20%,35%,and 50% reactive magnesia-mixed concrete has significantly improved mechanical properties after carbonization than ordinary concrete;The compressive strength and splitting tensile strength and the elastic modulus of the 35% reactive magnesia-mixed concrete are the highest of the four concrete different mix ratios;When the reactive magnesium oxide content beyonds 50%,the strength of the concrete will decrease because of the insufficient carbonization reaction of magnesium oxide hydrate in concrete.The content of reactive magnesium oxide should not be too high.(2)Replace the cement in reactive magnesia concrete with silica fume with different content(0%,3%,6%,9%)on the basis of concrete mix ratio of the Previous chapter,and test the compressive strength of the concrete.The study show that with the addition of silica fume,the compressive strength of reactive magnesia carbonized concrete has increased.From 0 to 6% addition of silica fume,the compressive strength of the concrete is increased while the amount of silica fume increases.And while the Silica fume content exceeds 9%,the compressive strength of the concrete begins to decrease.6% is the appropriate content of silica fume.(3)The bonding performance between ordinary concrete and reactive magnesia carbonized concrete with the light round steel bars and threaded steel bars is compared through the indoor model tests.The results show that the bonding performance betweenreactive magnesium oxide concrete and steel bars is improved compared to ordinary silicate concrete Significantly.(4)The carbonization depth of reactive magnesium oxide concrete under accelerated carbonization conditions was studied through laboratory experiments.The carbonization depth model of reactive magnesium oxide concrete was established based on the experimental data.And the result show that the carbonization depth of reactive magnesium oxide concrete was proportional to the square root of carbonization time.(5)The experimental analysis of water resistance of reactive magnesia concrete was conducted,and the relationship curve between the strength of reactive magnesia concrete and the water content of the concrete was summarized,and the results show that the reactive magnesium oxide carbonized concrete has good water resistance.Test the freeze-thaw cycle resistance of reactive magnesium oxide carbonized concrete,and the results show that the quality loss and compressive strength loss of concrete after freeze-thaw cycle is small.The reactive magnesium oxide carbonized concrete has good freeze resistance.Figure[41] table[31] reference[58]...