Abstract— <p>The paper discusses the possibility of obtaining a cement-free composite binder based on mechanically activated saponite-containing powder and slaked lime. The binding and hydrophysical properties of the two-component system “MSP–Ca(OH)₂” in a wide range of changes in the mass content of the mixture components were determined. IR spectra of sample compositions and electronic photographs of the chipped surface of samples after physical and mechanical testing were analyzed. It has been shown that a composition based on mechanically activated saponite-containing powder and slaked lime exhibits the properties of a cement-free binder, with the mass optimal content of mineral components (10–30% Ca(OH)₂) with W/S = 0.45 allows to obtain a mixture with a compressive strength of 8–11 MPa. The maximum value of strength in a moisture-saturated state is observed with a content of Ca(OH)₂ 30 wt %. Increasing the concentration of calcium hydroxide above 30 wt % in the system leads to a decrease in the strength characteristics of the composite. It has been established that preliminary acid activation of saponite-containing powder leads to an increase in its pozzolanic capacity due to an increase in the content of the amorphous component, which is capable of entering into chemical interaction with lime to form needle-shaped crystals of aluminous tobermorite.</p>