The currently designed building materials should be in line with the principles of sustainable development, low-emission economy and circular economy. Guided by these criteria, waste powder containing epoxy resin, calcite and barite was included in the concrete mix. The waste material was used as an additional component of the concrete mix in the amount of 7.5% of the cement mass, without reducing the amount of binder. At the same time, the water/cement ratio was used at a level of 0.44 to 0.56. The obtained concretes were characterized by good workability and fluidity, despite the modifier used. Tests were carried out to assess the resistance of the obtained concretes to the effects of sulphates and chlorides. After 28 days of curing, the concrete samples were immersed in a 5% sodium sulphate solution and a 5% sodium chloride solution. After 48 days of exposure, a decrease in the compressive strength of the concrete samples modified with waste powder was noted in relation to the control concretes. In the case of samples exposed to sulphate salts, the introduction of 7.5% by weight of waste into the concrete composition was associated with a reduction in compressive strength by 8% or 9.9%, respectively, for a higher or lower water/cement ratio. The compressive strength of concrete immersed in sodium chloride solution was reduced by 9.9% for samples containing 7.5% waste at a water/cement ratio of 0.56 and by 5.4% when the water/cement ratio was 0.44. The mass of the samples was also monitored during the test. An increase in the mass of all samples, modified with waste powder and those without the modifier, was noted. The average mass changes for concretes immersed in sodium sulphate solution ranged from 0.16% to 0.31%, and for sodium chloride solution from 0.15% to 0.24% and were dependent on the water-cement ratio and the presence of waste in the concrete mix. The analysis of the durability of concretes showed no harmful effect of the modifier on the microstructure of the cement paste resulting from the action of corrosive reagents. The conducted FTIR, XRD, SEM tests did not confirm the formation of, among others, secondary ettringite, which could cause microstructural damage to the cement paste by generating expansive forces, especially in small pores due to the high crystallization pressure. The proposed method of modifying the composition of concrete is promising and can help reduce the problem related to waste management, but also help reduce greenhouse gas emissions.

Sustainable concretes; circular economy; low carbon economy; waste powder; chemical resistance