由山东省建筑科学研究所研制的、由几个厂家生产的NC-Ⅱ型混凝土负温早强剂,是一种用于混凝土冬季施工的新型外加剂。它不仅在常温下是一种高效早强剂,而且在正负交变的自然气温条件下也是一种有效的早强、增强剂。在室外-11～+10℃温度条件下养护的掺NC-Ⅱ剂的混凝土,28天强度却达到标养28天强度的121%。因此,在上述温度地区,使用矿渣水泥或 The NC-II concrete negative temperature and early strength agent developed by Shandong Institute of Building Research and produced by several manufacturers is a new type of additive for concrete construction in winter. It is not only an effective early strength agent under normal temperature, but also an effective early strength and enhancer under the condition of natural and negative alternating natural air temperature. In the outdoor -11 ~ +10 °C temperature curing concrete mixed with NC-II agent, the strength of 28 days to reach the standard strength of 28% of 28 days. Therefore, in the above temperature areas, use slag cement or