不同养护方式下可再分散乳胶粉改性砂浆的性能

Performance of Redispersion Emulsoid Powder Modified Mortar under Different Curing

研究了三种不同养护方式(60℃蒸汽养护、饱和石灰水浸泡养护、早期水中-后期空气中养护)对掺入不同剂量的乙烯-醋酸乙烯共聚物可再分散乳胶粉(EVA乳胶粉)改性砂浆性能的影响规律。结果表明:随着EVA乳胶粉掺量的增加,砂浆的流动度先增大后减小,吸水率先减小后增大,且EVA掺量为4%时,砂浆流动性最好,掺量为6%时砂浆吸水率最小;砂浆抗折强度先增大后减小,且在4%掺量时取得最大值,而抗压强度一直减小,砂浆的压折比呈现出先减小后保持基本不变,并在4%乳胶粉掺量时有较低值;蒸汽养护最有利于聚合物砂浆结构的致密及强度的发展,而饱和石灰水浸泡养护对其致密性和强度最不利。

The research of the influence rules of three different curing methods （60℃ steam curing, saturated limewa- ter soaking curing, Water immersion early and stand in air latterly） on performance of mortar modified with ethylene/vinyl acetate copolymer latex powder （EVA latex powder） in varies of dosages is carried out. The results show that with the increasing of EVA dosage, mortar＇s fluidity increases first and then decreases, while the water absorption reduces first then arises, the fluidity of mortar reaches the best when EVA dosage is 4%, and water absorption is lowest when EVA is 6%; The flexural strength of mortar increases first and decreases later and gets the maximum value when EVA content is 4%, moreover, compressive strength keeps reducing, in addition, the ratio of compressive strength to flexural strength of mortar first decreases and then remains essentially unchanged. Steam curing is most conducive to the structure densification of the polymer mortar and its strength, while the saturated limewater soaking curing creates just the opposite effect.