超缓凝高效减水剂GCL1-5的性能研究

Study of Super-Retarding High range Water Reducer GCL1-5

为了适应大型混凝土工程和高温施工的需要,本文在改性木素磺酸钙缓凝高效减水剂GCL1的基础上进一步进行化学改性,研制出超缓凝高效减水剂GCL1 5,并对其进行性能研究。结果表明:掺加0 4%GCL1 5时,水泥净浆在20℃下初凝时间为26h25min,比未掺加减水剂时延缓了23h;40℃下初凝时间为4h50min,比未掺加减水剂时延缓了3h,缓凝效果显著。20℃时2h内的相对流动度损失为30%,40℃时为42 8%,能明显减小流动度损失。掺加GCL1 5的硬化水泥7d、28d、90d的抗压强度比分别为114%、125%、136%。扫描电镜研究的结果表明,GCL1 5使硬化水泥的后期强度明显提高的原因是GCL1 5能使水化产物致密、水泥石毛细孔径变小。

To suit the needs of largescale concrete works and construction at high temperature,superretarding highrange waterreducer GCL15 was developed by way of further chemical modification based on the retarding high range water reducer GCL1 made of modified calcium lignosulfonate. Study of the preformance of GCL15 showed that ,when 0.4% GCL15 was added, the initial setting time of cement paste at 20℃ was 27 hours and 25 minutes, 23 hours longer than that with no water reducer added while at 40℃ it was 4 hours and minutes, 3 hours delayed. Its retarding effects were remarkable. At 20℃ relative loss of fluidity of cement paste after addition of 0.4% GCL15 was 30% within 2 hours while at 40℃ was 42.8%. GCL15 appeared to be able to decrease loss of fluidity greatly. The 7day, 28day and 90day compressive strength Rations of hardened cement with GCL15 added reached 114%, 125% and 136% respectively. SEM study showed that great improvement of laterstage strength of hardened cement was attributed to the fact that GCL15 could make hydrated products denser and capillary porosity smaller.