Frost Resistance Research Of Concrete Containing Scrap Rubber Powder

Rubberized concrete as a new type of concrete, which caused widespread interest in the field. Now most studies on rubberized concrete focused on the mechanical properties, anti-permeability, shrinkage, the anti-freeze durability of rubberized concrete in sulfate or seawater environment is still rarely reported.This paper studies the anti-freeze durability of rubberized concrete mixed with powder particle size of 120 mesh fine rubber powder(30 kg/m3) in different corrosive medium.Do some researches on the freeze resistance tests in freshwater,5% Na2SO4 solution, seawater, analyses the anti-freeze mechanism from microcosmic viewpoint. At the same time, fresh concrete properties and hardened concrete mechanical properties are also tested.The results of this paper are:(1)after added fine rubber powers, the slump and apparent density decrease, rubberized concrete's compressive resistance and elastic modulus also decrease. (2)Compared with ordinary concrete, rubberized concrete shows better freeze resistance in this three erosion solution, the enhancement on freeze resistance is obvious by adding rubber power into concrete under the effect of freez-thaw and media corrosion, and this enhancement decreases with the water-cement ratio increasing; rubberized concrete shows different failure patterns in different media corrosion:in seawater, the freez-thaw damage mianly bases on relative dynamic elastic modulus rapidly decreasing, the surface scaling is obvious,in 5% Na2SO4 solution, the freez-thaw damage mianly bases on mass loss,which caused crack suddenly, and relative dynamic elastic modulus decrease slow compared with seawater,the mass loss in freshwater is similar to 5% Na2SO4 solution,but the relative dynamic elastic modulus decrease slowest compared with the seawater and Na2SO4 solution condition. (3) Mercury injection test shows micropore content is increasing with freezing and thawing, the increasing in seawater and Na2SO4 solution is slower than in fyeshwater, may be due to salt crystallization filling micropore; the bubble test shows putting fine rubber particles whose size are equal to put lots of "bubbles", the hole structure of concrete is improved; the SEM test shows freez-thaw cycle is a process which the concrete structure from close to loose until destruction,the rubber power that as filling material don't take part in the reaction of concrete.