两性接枝共聚物超塑化剂对水泥早期水化的影响

采用水化热测定仪及非接触式电阻率测定仪研究了两性羧酸类接枝共聚物超塑化剂(SSP)对硅酸盐水泥水化热性能及交变电场下电阻率的影响.结果表明:SSP在不延缓水泥正常凝结的前提下,能有效降低水泥早期水化放热量和水化放热速率,延缓水化放热峰值出现时间.SSP掺量为0.3%(质量分数)时,同空白水泥浆体相比,其1 d水化热降低了83%,水化热峰值出现时间延缓了20 h,最高水化放热速率降低了将近50%.SSP使水泥浆体的电阻率平衡期延长,且SSP掺量高的水泥浆体在凝结硬化阶段具有较大的电阻率增长斜率.

Influence of Amphoteric Polycarboxylate Copolymer Superplasticizer on Early Hydration of Portland Cement

The effect of a new kind of amphoteric carboxylic acid-based graft copolymer concrete superplasticizer(SSP for short) on thermology of hydration and electrical resistivity was investigated by means of non-contacting electrical resistivity measurement device and calorimetric device.According to experimental results,the SSP does not retard cement hydration,but ture can reduce the rate of heat evolution,the heat amount of early hydration of cement paste,and delay the time to reach highest hydration temperature.The SSP at a dosage of 0.3% reduces the heat amount of 1 d hydration by 83%,delays the time to reach highest hydration temperature about 20 h,and reduces the rate of heat evolution by about 50% compared with reference cement paste.The electrical resistivity results also indicate that the electrical resistivity increases with increase of the SSP dosages and the induction period is greatly delayed.