低温施工复合外加剂试验研究

Test Study on Multiplex Additive for Low-temperature Constructing

水泥稳定砂砾在多年冻土地区低温条件下应用普遍出现了板体性差、强度低等问题,综合考虑早强、抗冻、微膨胀、延迟时间、方便施工等因素,研制了水泥稳定类材料低温施工使用的CS-1型水泥复合外加剂。为了检验CS-1型水泥复合外加剂的实际使用效果,对掺入外加剂基层混合料的强度、收缩、抗冻和疲劳等关键路用性能与未掺外加剂基层混合料进行了对比试验分析,并在青藏公路整治改建工程中进行了试验路验证。研究表明,CS-1型水泥复合外加剂可以明显加快混合料低温早期强度的形成,显著提高混合料低温下的早期强度,提高水泥稳定砂砾低温区的抗温缩开裂能力,改善抗冻耐久性,在低应力水平作用范围内可以延长使用寿命,适宜于多年冻土地区等低温条件下的水泥稳定基层混合料使用。

Some problems, for example unformed harden or low strength, occured widely in the cement stabilized gravel base under the low temperature condition of the permafrost area. Synthetically considering such factors as early strength, frost resistance, small expand, delaying time and convenient construction, the cement multiplex additive CS-1 was developed specially for the cement stabilized gravel constructing under the special low temperature. To verifying the actual applied effect of the CS-1, the key road performance including strength, contract, frost resistance and fatigue of the base mixture mixed with the CS-1 were tested and compared with the mixture without the CS-1. The test road with the additive is built in the Qinghai-Tibet highway. It is pointed that the CS-1 additive can evidently accelerating the early-strength formation, and remarkably enhance the low-temperature early strength.The thermat-shrink crack resistance and the frost resistance of the base mixture will be evidently improved by mixing the CS- 1. The service life of the base under the low stress level will be prolonged. The results indicated that the cement additive type CS-1 is feasible to be used for the cement stabilized base under the special condition.