IMPACT THE TREATMENT TYPES OF RECYCLED CONCRETE AGGREGATES ON CONCRETE STRENGTH

Abstract

Problem statement. The National Strategy of waste management in Ukraine until 2030 provides the creation of conditions for market development of usage recycled construction and demolishing waste including the ways of characteristic determination to obtain the regulations for recycled construction and demolishing waste that will let re-use and disposal. One of ways the re-use of deconstructed concrete is the obtaining coarse and fine aggregates for subsequent manufacturing of building materials and products. The ordinary way of recycled aggregates obtaining includes crushing stages that do not allow recovering the purified, i. e. cement-free, aggregates. Therefore, it is necessary to search the effective methods of treatments for producing high quality recycled aggregates. The purpose of the article is compressive strength evaluation of concrete samples with usage of aggregates obtained from waste of railway reinforcement concrete sleepers. The comparison of concrete strength has been done for coarse aggregates which are cleaned with mechanical treatment or impregnation by sodium silicate solution. Conclusions. It is established that both the mechanical purification from old cement-sand mortar rests and impregnation enhance physical and mechanical properties concrete comparing to concrete with untreated aggregates. The mechanical treatment increases the compressive strength and reaches 98 % of compressive strength for concrete with natural aggregates. The impregnation of sodium silicate increases at 10 % concrete strength compare with strength of concrete with untreated aggregates. So, both treatment methods of recycled coarse aggregates can be used for concrete manufacturing with appropriate strength.