Dispersed reinforcement as a factor of increasing the quality of the lightweight cements
The use of lightweight cement materials for the construction of oil and gas wells is one of the main conditions to ensure the required lifting of the cement height to the design height. Herewith, to improve the support integrity it is advisable to use expanding cements, which in the intervals of using lightweight cements do not give a good effect because of the increased water-cement ratio. This leads to an increase in the distance between the products of hydration and the decrease in pressure developed by the expanding additive. A prospective way to increase the expansion effect in lightweight cements is a dispersed reinforcement. Studies have shown that reinforcing additives contribute to the expansion of lightweight cements by transferring pressure from the expanding additive to cement hardening products through a framework formed by fibro-reinforcing elements. It increases the strength limit of the cement stone for bending and compression as well as improves impact resistance and increases the expansion effect. At fiber concentrations up to 0,5 %, it does not significantly affect the rheological characteristics of the cement material. All types of fibers do not significantly affect the water loss of cement solutions, but they effectively reduce their water separation.