Study On Polymer Modified Admixture Concrete In Salt-frozen Environment Durablilty

Concrete is a common building material in road engineering,and in the cold zone,the freezing-thawing circulation environment is one of the important factors affecting its durability.Especially in some special areas,such as winter de-icing salt environment,the durability of ordinary concrete will be eroded by chlorine salt and freeze-thaw cycle,greatly shortening the service life of concrete pavement.In recent years,polymer concrete has gradually entered people's field of vision,because of its good mechanical properties and excellent durability known to people.In addition,the addition of mineral admixtures has a certain effect on the durability of concrete.This paper mainly studies the basic mechanical properties and durability of polymer modified concrete mixed with different types of mineral admixtures in road de-icing salt environment from the material level.In this paper,four kinds of concrete are used: ordinary concrete,concrete with only fly ash(35%),concrete with only silica fume(5%),concrete with double fly ash and granulated blast furnace slag powder(35%+20%).Among them,fly ash and slag powder are 1:1 replacement cement and silica fume is 1:3replacement cement.The polymer emulsion made of waterborne epoxy resin prepared by the post-blending method were made of concrete and tested with the poly-ash ratio of 0%,5%,10%,15% and 20% respectively.The test results show that: 1.The slump of concrete gradually decreases with the increase of the aggregate ratio,which is mainly caused by the increase of the aggregate ratio and the addition of colloidal curing agent.In order to ensure normal construction,the ash accumulation ratio should be less than 15%;2.In terms of compressive strength,the 28 d compressive strength of concrete in each group tended to decrease gradually with the increase of the poly(cement)ratio.The strength of ordinary concrete with a cement(cement)ratio of 20% decreased by about 14%,which was the group with the largest decline.In addition to silica fume concrete,the compressive strength of other mineral admixtures on 7d and28 d of concrete is generally lower than that of ordinary concrete group,but the compressive strength on 56 d of each group is generally higher than that of ordinary concrete group.3.In terms of resistance to chloride ion permeability,theelectric flux of concrete in each group decreased significantly with the increase of the poly(cement)ratio.When the poly(cement)ratio was 10% and 20%,the electric flux of ordinary concrete decreased by 60% and 68%,respectively.The electric flux of concrete mixed with mineral admixtures was lower than that of ordinary comparison specimens,among which the electric flux of concrete specimens mixed with silica fume was the smallest,decreasing by about 46%compared with ordinary concrete.4.As for the resistance to salt freezing,the relative modulus of motion increased with the increase of the proportion of accumulated ash.Under the condition of 200 times of salt freezing,when the proportion of accumulated ash was 10%,the relative modulus of motion was94.7% and 83.8% in the general group.In the same condition,the relative modulus of fly ash mixed with coal powder was only 78.9%,but the modulus of fly ash mixed with 10% was 92.4%.The relative kinematic modulus of concrete specimens mixed with silica fume was 92.6%,and the relative kinematic modulus of concrete specimens mixed with silica fume was 95.9% and 97.1%,respectively.5.Through analysis of technical performance and economic benefit,it is known that concrete with silica fume only mixed with 10% aggregate ratio is better than other groups,which has a broad application prospect.