An investigation of the influence of various types of cement on the physicochemical properties of autoclaved aerated concrete

Introduction. The article addresses the influence of various types of cement on the physicochemical properties of the aerated concrete mix and finished products that have D600 density and are manufactured according to the impact technology. The study is aimed at improving the rheological properties of the mix and the operational parameters of autoclaved aerated concrete (AAC). The authors study a reduction in the “carbon footprint” of AAC CEM II. The aim of the study is to improve the physicochemical properties of the aerated concrete mix to stabilize the AAC production process and increase the strength-density ratio of the ultimate product. Materials and methods. To analyze the influence of various types of cement on AAC, trial batches were manufactured. The following grades of cement were used in testing: CEM I 52.5 N, CEM I 42.5B, PC 500-D0-N, CEM II/A-M (S-I) 42.5N, CEM II/A-L 42.5N, CEM II/A-L 42.5B. Chemical and mineralogical compositions of cements were identified as factors affecting the rheological properties of the aerated concrete mix. The properties of the aerated concrete mix were evaluated against the following parameters: consistency identified using the Southard viscosimeter, mix boiling point, boiling time, plastic strength, and cutting temperature. Final properties of products were evaluated against such parameters as strength and density. The flow was measured using the Southard viscosimeter; the value of plastic strength was identified using the penetrometer. The strength and density of ACC were identified pursuant to GOST (State Standard) 10180-2012 and GOST 12730.5-2018. Results. The authors have identified dependences between changes in the rheological properties of the mix, operational parameters of AAC and the mineralogical composition of cement. The authors present graphs describing dependencies between plastic strength and the C3A content, plastic strength and the MgO content, ultimate strength and the MgO content, strength and the C3S content; density and the C3S + C4AF content. A graph describing the effect of limestone and slag additives on the mix consistency is presented. The authors describe the way the amount of alkaline oxides in cement affects the ultimate strength of AAC. The types of defects caused by particular types of cement have been identified. The cement, having the highest value of the strength-density ratio, has been selected. Conclusions. It is shown that the cement, containing limestone and slag additives, cannot deteriorate any physicochemical or operational characteristics of AAC. The use of CEM II reduces the cost of production and the “carbon footprint”.