Drilling cement

Drilling cement.

Drilling cement is mainly characterized by a long-term one (often from 2 do 3 hours) the invariability of the consistency of slurries as well as mortars and concretes made of this cement. This feature is indispensable for initializing (cementation) in order to seal the rock mass and cracked concrete structure through previously drilled holes and when transporting the mixture to large (up to several km) depth, which often happens in mining and opencast works. This role is played by cement with a very low C3A content (0-3%) i C3S (do 60%) and a shallowness of approx 2500 cm²/g wg Blaine. The necessary degree of liquidity and duration, and the required final properties after hardening (min 20 MPa) can be regulated by choosing the right additives and admixtures. Choosing admixtures, must be taken into account, what 33 m in depth, the temperature in the ground increases by 1°C. When working to a depth above 0,5 km, The cement must therefore be supplemented with a setting retarding admixture according to the high ambient temperature involved. Simultaneously, hardened product should get after 8 hours from the start of bond strength 1,5-3,0 MPa.