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以亚硫酸氢钠对经高碘酸钠氧化处理的棉浆纤维进行磺化改性,制备氧化-磺化纤维素(OSC),并对其用作混凝土减水剂的性能进行研究。结果表明:氧化-磺化纤维素的减水率随磺酸基取代度增大而提高;氧化-磺化纤维素对水泥具有一定的缓凝作用;当其取代度为0.453,折固掺量为0.8%时,测得的水泥砂浆减水率、净浆凝结时间和3、7、28 d水泥砂浆抗压强度比等指标均符合GB/T 8076—2008《混凝土外加剂》中缓凝型高效减水剂的要求。通过SEM微观结构分析表明:水泥砂浆中掺入氧化-磺化纤维素后,由于缓凝作用导致水泥初期水化反应发展缓慢,而经较长时间(如28 d)后硬化水泥结构比基准样密实、强度更高。因此,OSC有望成为具有实际应用价值的混凝土高效减水剂。
Sulfonation of sodium cotton pulp oxidized by sodium periodate was carried out with sodium bisulfite to prepare oxidized-sulfonated cellulose (OSC), and its properties as a concrete water-reducing agent were studied. The results showed that the water reducing rate of oxidized-sulfonated cellulose increased with the degree of substitution of sulfonic acid group. Oxidation-sulfonated cellulose had some retarding effect on cement. When the degree of substitution was 0.453, Is 0.8%, the measured cement mortar water-reducing rate, the coagulation time and 3,7,28 d cement mortar compressive strength ratio and other indicators are in line with GB / T 8076-2008 “concrete admixture” in retarding type Superplasticizer requirements. The microstructure analysis of SEM showed that the initial hydration reaction of cement was slowed down due to retarding effect after cementing with oxidized-sulfonated cellulose. After a long period of time (eg 28 days) Dense, higher strength. Therefore, OSC is expected to become a concrete superplasticizer with practical value.