Analysis of Durability Properties of Concrete With Recycled Constituents

Beton je jedan od najkorištenijih materijala današnjice. Zbog svoje raznovrsne primjene njegova proizvodnja raste iz dana u dan. Prema tome postavlja se pitanje kako proizvodnja betona utječe na okoliš i održivi razvoj. Komponenta betona čija proizvodnja troši najviše energije i ostavlja veliki ugljični otisak je cement. Također, eksploatacija i proizvodnja prirodnog agregata kroz različite aktivnosti ostavlja značajan ugljični otisak. Iz tog razloga nastaje potreba korištenja alternativnih materijala kao zamjena cementa i prirodnog agregata kako bi se smanjio ugljični otisak prilikom proizvodnje betona. Cilj ovog rada je analizirati utjecaj uporabe recikliranih komponenti u betonu na trajnosna svojstva samog betona. Utvrđeno je da proizvodnja cementa za beton ima najveći udio u stvaranju CO2 pri proizvodnji betona, čak do 85%. Prema tome, značajniji utjecaj na čuvanje okoliša ima korištenje pucolanskih materijala kao zamjena cementu, nego upotreba recikliranog betonskog agregata. Napravljeni su uzorci tri različite betonske mješavine od recikliranih materijala pomoću kojih su provedena ispitivanja plinopropusnosti, dubine prodora vode pod tlakom te habanja. Reciklirani materijali korišteni u ovom istraživanju su metakaolin, reciklirani betonski agregat, vunena vlakna, reciklirana voda te PVC piljevina. Ispitivanja su provedena radi utvrđivanja kako upotreba recikliranih materijala u betonu utječe na njegova svojstva trajnosti. Rezultati ukazuju da se korištenjem recikliranih materijala u betonu postižu bolja svojstva trajnosti u pogledu nepropusnosti. Uzevši u obzir sva tri ispitivanja ocjenjuje se da beton RBA30+W koji sadrži 30% RBA i vunena vlakna ima najbolja svojstva trajnosti. To dovodi do zaključka da se korištenjem određenih recikliranih materijala u betonu mogu postići ista ili bolja trajnosna svojstva uz reduciranje štetnih plinova pri proizvodnji betona.Concrete is one of the most used materials today. Its production is growing perpetually due to its various applications. Therefore, the question arises whether concrete production affects the environment and sustainable development. Cement is a concrete component whose production consumes the most energy and leaves a large carbon footprint. Moreover, the exploitation and production of natural aggregate through various activities leaves a significant carbon footprint. For this reason, there is a need to use alternative materials to replace cement and natural aggregate to reduce the carbon footprint during concrete production. The aim of this research was to analyze how the use of recycled components in concrete affects the durability of concrete itself. It was found that the production of cement has the largest share in the creation of CO2 during concrete production; up to 85%. Therefore, the orientation towards the use of pozzolanic materials as a substitute for cement has lower environmental impact than the use of recycled concrete aggregate. To test this hypothesis, samples of four different concrete mixtures were made from recycled materials. They were tested for gas permeability, depth of water intrusion under pressure and wear. Recycled materials used in this research were metakaolin, recycled concrete aggregate, wool fibers, recycled water, and PVC sawdust. Tests were conducted to determine how recycled materials in concrete affect its durability properties. The results indicate that the use of recycled materials in concrete improves durability properties in terms of impermeability. Considering all three tests, it is estimated that concrete RCA30 + W containing 30% RCA and wool fibers has the best durability properties. This leads to the conclusion that using certain recycled materials in concrete can achieve the same or better durable properties while reducing discharge of harmful gases during concrete production