Study On Durability Of Waste Rubber Cement Mortar

Scrap tire rubber is a kind of polymer material that is difficult to degrade in the natural environment.How to deal with it is related to global environmental protection and resource utilization.After being crushed into granules,it is blended into a mortar to prepare a rubber mortar,which not only can modify the mortar,but also provides an effective way for the recycling of used tires.In this study,based on ordinary mortars,equal-volume replacement sands of waste tires with different particle sizes were mixed into the mortar,and their mechanical properties,durability,and pore structure were studied and analyzed.The main conclusions are as follows:(1)The effects of different rubber particle sizes and blending on the compressive strength,flexural strength and failure characteristics of mortar were investigated.The results show that the strength of the rubber mortar decreases,and the strength gradually decreases with increasing rubber content.When the blending amount of rubber is 5% or 10%,the strength is reduced by about 20% compared with the ordinary mortar;and when the blending amount reaches 20%,the strength is reduced by 50% compared with the ordinary mortar.The incorporation of rubber particles causes the mortar to change from brittle failure to plastic failure.(2)The incorporation of rubber reduces the chloride ion permeability coefficient of the mortar.After 200 cycles of freeze-thaw cycles,the surface of the rubber mortar specimens had a certain degree of exfoliation,but there was no great loss of quality.After the freeze-thaw cycle,the strength of rubber mortar showed a decreasing trend compared with that of unfreeze-thaw specimens.The carbonization depth of rubber mortar is lower than that of ordinary mortar.(3)The bond at the rubber-cement interface is weak.The incorporation of rubber increases the porosity of the mortar to a certain extent;the porosity increases linearly with the increase of the rubber content.When the rubber content reaches 20%,the most probable pore size is 2.5 μm,reaching the micron level;while the most probable pore size of ordinary mortar is 26.3 nm.The measurement result of the contact angle between the distilled water and the surface of the rubber particles was 115° and it was hydrophobic.The amount of rubber increased,the capillary water absorption also decreased accordingly,the capillary water absorption and time have a good correlation;capillary absorption coefficient with the extension of the soaked specimen no longer increase;measured by the water absorption rate of the average pore size parameters With the increase of rubber content,the average pore size uniformity increases with the increase of the amount of rubber.The incorporation of rubber into the mortar increases the capillary pore content of the mortar,but due to its hydrophobic nature,it blocks the connectivity of these pores.Therefore,the incorporation of rubber reduces the permeability of the mortar and also makes it durable.Sex played an improvement role.