Laboratory experiments on the negative-temperature, early-strength slurry system

In the environment of negative temperature, the liquid water in the conventional cementing slurry suffers segregation and freezing, hydration reaction slows down and even stops completely, and consequently the cementing can be hardly carried out. To solve this problem, a series of experimental studies were conducted, including the optimization of hydration performance, the regulation of setting time, the evaluation of rheological property and the test of compression strength under negative temperature. And accordingly the negative-temperature slurry system suitable for permafrost regions were determined with the antifreezing accelerating agent SCLC-1 (mass fraction 20%) as the slurry preparation solution and the modified high alumina cement as the basic-water hardening material, together with 0.5% hydramine accelerating agent TEL and 1%-3% setting time regulating agent. The experimental results show that this system has excellent negative-temperature curing performance and rheological property. Under −18 ℃, it gets cured within 0.5−3 h and its compression strength is up to 3.5−9 MPa after 24 h. It can realize curing and strength under negative temperature, so as to satisfy the construction requirements of cementing in permafrost regions.