Durability characteristics of concrete and reinforced concrete with recycling (concrete) rubble

Introduction. One of the most important reserves for saving material and energy resources in the construction industry is the re-involvement of recycled (concrete) crushed stone in the production sector, in particular for the production of heavy concrete of classes B7,5–B35 for general construction purposes. Solving this problem will practically ensure the implementation of the most important principle of waste-free technological processes (in the production of precast and monolithic concrete and reinforced concrete structures) and create conditions for fulfilling important social, economic and environmental tasks. Aim. Conducting experimental studies to determine the standardized durability characteristics of concrete and reinforced concrete based on recycled (concrete) crushed stone and natural sand, as well as comparing them with similar concretes based on natural crushed stone and sand. Materials and methods. For the research, recycled (concrete) and granite (natural) crushed stone according to State Standard 8267-93 were used as coarse aggregates. Natural sand according to State Standard 8736-2014 was used as a fine aggregate. Portland cement according to State Standard 31108-2020 was used as a binder. Superplasticizer C-3 according to State Standard 24211-2008 was used as an additive. The mixing water was used according to State Standard 23732-2011. Results. Concretes based on recycled crushed stone and natural sand have slightly lower strength, density and identical indicators of water resistance and frost resistance compared to similar concrete based on natural crushed stone and natural sand. Conclusions. Based on the results of the work carried out, it was revealed that concrete based on recycled crushed stone and natural sand ensures the initial passive state of steel reinforcement and retains the passive state of steel reinforcement for a long time (more than 100 years) with a protective layer thickness of 10 mm. Concretes based on recycled crushed stone and natural sand can be used as traditional structural concretes for general construction purposes.