【摘要】 以氯磺酸为磺化试剂,半干法制备了磺化淀粉,并对其用作水泥减水剂的性能进行了系统的研究。结果表明:磺化淀粉减水率随磺酸基取代度增加而增加,当其取代度达到0.060 4,质量分数为0.3%时测得的水泥净浆减水率、净浆标准凝结时间和3 d、28 d砂浆强度等各项指标均达到高效减水剂的国标要求,磺化淀粉对水泥还具有一定的缓凝作用。通过XRD和SEM,对掺加了磺化淀粉的水泥材料进行了微观结构表征,结果表明:磺化淀粉掺入水泥浆后,由于缓凝作用导致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。而且磺化淀粉掺量0.3%(质量分数)即可达到高效减水剂的要求,比现有的高效减水剂掺量都低。更多还原

【Abstract】 Sulfonated starch was prepared by semidry method using ClSO₃H as sulfonating reagent and CH₂Cl₂ as dispersant.Its performance as water-reducing admixture for cement is studied systematically.The results showed that the water reducing ratio of sulfonated starch is increased with the degree of substitution（DS）.When the DS reached（0.060 4） and the mass fraction of sulfonated starch is 0.3%,the indexes tested including the water reducing ratio,the setting time of cement paste and the compressive strength of mortar（3 d and 28 d） all meet the GB requirements of superplasticizing admixture.In addition,the sulfonated starch presents some set retarding effects.Results of XRD and SEM tests show that the hydration is slow at early days when sulfonated starch is mixed into the cement paste.But after a long period of hydration such as 28 days,the structure of the hardened cement paste becomes more uniform and compact than that of the control,and the compressive strength is also stronger.Moreover,the mass fraction of sulfonated starch needed is lower than that with other superplasticizers.更多还原