AN EXPERIMENTAL INVESTIGATION ON IMPROVING THE MEDIUM AND LATE-AGE COMPRESSIVE STRENGTHS OF CLASS G OIL WELL CEMENT

In this study, the effects of particle size distribution improvement and dense packing techniques on the 28- and 90-day compressive strengths of class G oil well cement have been investigated. It was observed that limited improvements in the particle size distribution of cement (regarding industrial possibilities) cannot result in a significant increase in 28- and 90-day compressive strengths. Also, in the application of the dense packing technique, silica fume and limestone powders with the grain size less than 45 micrometers cannot be utilized as substitutes for cement, because the addition of these materials simultaneously leads to the shortening of the setting times. The utilization of quartz powder as a filler exhibits partial pozzolanic properties at optimum substitution percentages, i.e. around 6 to 10% by weight; however, it can result in an almost 7% increase in the 28-day compressive strength of the hardened paste of the cement without any considerable effects on its setting times.