Abstract: This paper proposed the reasonable amount and the temperature of
adding silica flour after studying the strength retrogression of Romania
Sz oil cement at high temperature.The compound LC retarder added to the
slurry successfully retards the strength retrogression of cement and obvio-
usly improves the compressive strength of cement with silica flour.Its
thickening time and theology satisfy the requirement of 4000-5500m job.
This paper also analyzed the mechanism of LC raising the strength of
cement

Key words: Retarder Compressive strength Hydration Dispe