Complex modification of non-autoclaved foam concrete

Introduction. Cellular concrete is one of the most common building materials. Increase of its efficiency can be ensured by carrying out a complex modification. The paper proposes a formulation and technological solution for the production of non-autoclaved foam concrete, which consists in the use of a complex of modifying additives, including mineral dispersed and micro-reinforcing components. Their introduction contributes to stabilization of the foam concrete mixture, regulation of the processes of structure formation and control the performance of the finished material.Materials and methods. Portland cement of CEM I 42.5N grade, protein foaming agent “Etalon” were used. Modification of foam concrete was carried out by: quartz suspension obtained by wet milling of quartz sand, synthesized anhydrite, hardening activator Na2SO4, basalt and glass fibres. The main physical and mechanical characteristics of foam concrete were determined according to the current regulatory and technical documents. The microstructure was studied using scanning electron microscopy.Results. The influence of formulation factors on the operational quality indicators of non-autoclaved foam concrete for thermal insulation purposes was established, multicriteria optimization was carried out, rational compositions were determined. Materials with a density grade of D500 and a strength class of B1.5–B2 were obtained.Conclusions. The replacement of a part of the Portland cement binder with a dispersed modifier in combination with micro-reinforcing fibres makes it possible to obtain materials with improved properties at reduced production costs, namely, by optimizing the cellular structure, strength indicators increase while maintaining density and thermal conductivity values. This formulation solution leads to the compaction and strengthening of the interpore partitions, as a result, the “monolithization” of the matrix and the frame structure of the composite created by micro-reinforcing components. The material is characterized by polydisperse porosity with a wide range of pore sizes with a shape transitioning from regular rounded to polyhedral. As a result, the physico-mechanical and thermal insulation properties of non-autoclaved foam concrete are increased.

foam concrete, modification, dispersed components, basalt fibre, glass fibre, microstructure, non-autoclave hardening