Prospects for the use of fine-dispersed recycling products of concrete processing as mineral additives for the manufacture of building mortars

Abstract

Introduction. One of the most important reserves for saving material and energy resources in the construction industry is the re-involvement of recycling concrete materials (products of disposal of substandard concrete, reinforced concrete structures and products), in particular, highly dispersed powders with the prospect of their use as a mineral additive for the production of mortars for general construction purposes, in the production field. The implementation of this approach will practically ensure the introduction of the most important principle of waste-free technological processes (in the production of prefabricated and monolithic concrete, reinforced concrete structures and products) and create conditions for solving important economic and environmental problems.Aim. The aim of the work were the determining of the main physical and mechanical characteristics, comparative analysis of the mortar on Portland cement, as well as mortars with the replacement of a part of Portland cement (by 10, 15 and 25 %) with a recycling (concrete) fine powder with a specific surface area of 4500 cm2/g.Materials and methods. For the research, the following components were used: recycling (concrete) fine powder with a specific surface area of 4500 cm2/g, construction sand with a size modulus Mk = 2.31 (according to GOST 8736-2014), portland cement with CEMII/V-W 42.5N (according to GOST 31108-2020) slag, chemical additive “CENTRIPOR TFM 411R”.The selection of mortar compositions was carried out according to SP 82-101-98. Tests of mortar mixtures and mortars were carried out according to GOST R 58767-2019. Compliance with the compressive strength of mortars with the grade was determined in accordance with GOST R 58766-2019.Results. As a result of the work carried out, it is shown that fine-dispersed recycling concrete powder with a specific surface area of 4500 cm2/g can be used as a mineral additive (filler) for the production of mortars on a par with additives currently used in the construction industry of the country.Conclusions. The possibility of using fine-dispersed recycling concrete powder with a specific surface area of 4500 cm2/g as a mineral additive (filler) for the roductionof mortars on a par with additives currently used in the construction industry of the country. It has been shown that when 10 % of cement is replaced with recycled (secondary) fine powder with a specific surface area of 4500 cm2/g, the strength of building mortars of the M100–M150 grades increases and its structure improves.