Plasma modification of construction mortar components, an efficient method of increasing their performance

Introduction. The article considers the enhancement of physical and mechanical parameters of construction mortars used for recovering and repairing of building structures of communication collectors by using low-temperature nonequilibrium plasma. The study vindicated the expediency of treatment of construction mortar raw materials with LTNP to enhance their physical and mechanical parameters. The effect of plasma modification of raw materials on Portland cement phase composition, granulometric composition of the sand and mortar properties are analysed. The influence of multiplicity of silica sand and mixing water plasma treatment on the construction mortar strength is considered. Materials and methods. Cement-sand mortars are obtained from Portland cement of the CEM I 32.5N and CEM I 42.5N brands and silica sand with the fineness moduli of Mf = 0.32 and Mf = 0.63 and a separate fraction of less than 0.16 mm. Setting time and strength of the building mortars are defined according to GOST state standards in effect. Granulometric composition of the cement is explored by means of Analysette-22 particle size microanalyser, while ARL Optim’X spectrometer is used for studying phase composition of the cement stone, silica sand and cement-sand mortars. Results. It is determined that the plasma treatment of Portland cement reduces the grout normal consistency by 15 to 17 % and decreases its setting time by a factor of 3 to 4. Treatment of mixing water with the nonequilibrium low-temperature plasma removes its hardness, forming additional crystallization nuclei. The plasma-treated mixing water increases the curing rate of cement-sand mortars up to 50 % at the early stages of hardening and up to 30 % on the 28th day of hardening. Using plasma-treated silica sand decreases size of its particles and results in partial transition of the crystalline structure into the amorphous one. This reduces water demand of the sand by 10 to 18 %. Conclusions. The expedience of plasma treatment of raw materials to enhance the physical and mechanical properties of mortars is vindicated. Owing to the plasma modification of raw materials, quality and process characteristics of construction mortars are improved. The presented method of the plasma treatment of raw materials used to prepare the construction mortars is characterized with high degree of efficiency and convenience of application.