THE EFFECT OF THE HYDROTHERMAL TREATMENT METHOD ON OPERATIONAL CHARACTERISTICS OF SILICATE MATERIALS BASED ON CLAY AND VOLCANIC ASH

The research presents results on the use of Debub deposit loam and volcanic ash in the production of silicate materials under autoclaved and non-autoclaved conditions. For autoclaved conditions, an optimal mixture achieved a compressive strength of 22.75 MPa, an average density of 1955 kg/m3, and water absorption of 6.31 % with a composition of 10 wt.% loam, 25 wt.% volcanic ash, and a mixture activity of 6%. The non-autoclaved method yielded a compressive strength of 20.14 MPa with 40 wt. % loam, 25 wt.% volcanic ash, and a mixture activity of 6%. The corresponding average density, water absorption, and softening coefficient for the non-autoclaved samples were 1926 kg/m3, 8.58%, and 0.91, respectively. While the strength indicators for non-autoclaved samples are slightly lower than those produced by the autoclaved method, they remain within the recommended values for silicate products. It has been established that rock-forming loam minerals and volcanic ash actively interact with lime during hydrothermal treatment, both during autoclaving and steaming, forming fine- and coarse-crystalline new formations that provide high strength to silicate materials. In the State of Eritrea, where cost and environmental impact are paramount, autoclave and, especially, non-autoclave technology represents an optimal solution for the production of building materials.