Highly-Dispersed Wollastonite-Based Additive and its Effect on Fine Concrete Strength

Abstract

The effective highly-dispersed additive on the basis of the natural mineral wollastonite has been developed and studied. It enables obtaining fine concrete with the bending strength of up to 21.6 MPa and the strength of compression of up to 55 MPa, and the content of 0.5% (in terms of dry matter). The additive is a suspension of wollastonite after mechanical, and then ultrasonic processing in the aquatic environment of the anionic stabilizer of naphthalene-formaldehyde type. Due to the laser granulometry it has been ascertained that grinding wollastonite together with the anionic stabilizer leads to a change in the specific surface from 20 400 to 32 600 cm2/cm3 and to forming the particles with a modal diameter of 10.31 μm. After ultrasonic processing in the aquatic stabilizer environment the wollastonite particle size reduces to 0.4 μm. The positive heat and humidity effect on the structure and strength of the concrete with highly-dispersed wollastonite-based additive under the mode 3+4+3 h at the isothermal hardening temperature of 80оС is shown. The application of the developed additive in the fine concrete composition makes it possible to save up to 15% of cement due to the strength increase.