Composite Cement Based on Sulphoaluminoferrite Clinker: Corrosion Resistance

Introduction. The choice of cement for concrete composition is fundamental to preventing corrosion, as the type and properties of the binder determine the chemical and structural resistance of the cement stone to aggressive environmental influences. The use of corrosion-resistant cements, including sulfate-resistant, sulfoaluminoferrite, or pozzolanic cements, allows for the formation of a dense and low-permeability structure of cement stone, minimizing the formation of soluble compounds, and thereby significantly increasing the operational reliability of concrete in aggressive environments. Modern research is aimed at developing new cement compositions and technologies that ensure high corrosion resistance and durability of con-crete in aggressive environments. The aim of this research work was to study the cor-rosion resistance of a composite cement based on Port-land cement and a crystallization-coagulation additive (CCA) consisting of sulfoaluminoferrite clinker, micro-silica and a water-soluble polymer. Materials and methods. This study utilized Portland cement CEM 0 42.5N produced by Oskolcement CJSC and sulfoaluminoferrite clinker produced by Podolsk-Cement JSC. Microsilica fume (MS) UMK 85 (600) was used as a coagulation component. A water-polymer additive based on high-molecular poly-N-vinylpyrrolidone was used as a water-soluble polymer (WS). Corrosion resistance was studied under the influence of a 5% Na₂SO₄ solution. Corrosion resistance was assessed using the corrosion resistance coefficient, which was calculated as the ratio of the strength of a sample in an aggressive environment to the strength of a sample stored in water for the same amount of time. The degree of hydration of the samples and the degree of binding released during hydration of calcium hydroxide Ca(OH)2 samples were assessed by determining the amount of unhydrated cement using X-ray phase analysis (XPA). Results. This article examines the use of sulfoaluminoferrite clinker to produce composite cement with high corrosion resistance. The hydration of cement paste in aqueous and aggressive environments typical of industrial and marine environments was experimentally studied. It has been shown that the use of composite cement based on sulfoaluminoferrite clinker allows achieving high corrosion resistance of cement stone, which is due to the formation of stable hydrate phases. The developed composition was found to re-duce the rate of corrosion by 30% compared to standard Portland cement. The composite binder's re-sistance coefficient after 6 months reaches 1.18, qualifying it as corrosion-resistant. Conclusions. The study's results open up possibilities for the use of composite cement in hydraulic engi-neering, port facilities, and chemical industry facilities where high corrosion resistance is required.