Alternative rejuvenator as an additive to increase the share of reclaimed asphalt in asphalt mixture

Doktorska disertacija obravnava možnost povečanja deleža recikliranega asfalta v asfaltnih mešanicah ob dodajanju alternativnega pomlajevalca. Bitumen, ki je najpomembnejša komponenta asfalta in narekuje njegovo obnašanje, se med uporabo asfalta postara, zato se njegove lastnosti spremenijo. Z uporabo posebnih dodatkov, t. i. pomlajevalcev, bitumnu povrnemo njegove osnovne lastnosti. Na ta način lahko povečamo delež recikliranega asfalta, ki ga dodamo asfaltni mešanici. Alternativni pomlajevalec je bil s postopkom pirolize odpadnih gum na novo razvit produkt. Doktorska disertacija je sestavljena iz treh sklopov. V prvem sklopu smo na kratko predstavili različne pirolitske produkte, ki so nastali s spreminjanjem časa trajanja in temperature pirolize. Na podlagi njihovih lastnosti smo izbrali najprimernejši produkt za namen alternativnega pomlajevalca. V drugem sklopu smo preverjali vpliv pomlajevalca v različnih koncentracijah (3 %, 5 %, 10 % in 20 %) na viskoelastične lastnosti svežega in laboratorijsko staranega bitumna. S pomočjo standardnih mehanskih raziskav, reoloških raziskav in reološkega modeliranja smo dokazali, da alternativni pomlajevalec izboljša lastnosti staranega bitumna. Določili smo najprimernejšo koncentracijo bitumna, za uporabo v asfaltnih mešanicah z recikliranim asfaltom. V zadnjem sklopu smo s standardnimi raziskavami pokazali, da se ob dodatku pomlajevalca lastnosti asfaltnih mešanic z dodajanjem recikliranega asfalta izboljšujejo, prav tako pa lahko povečamo delež recikliranega asfalta. Ponovna uporaba recikliranega asfalta pomeni zmanjšanje odpadnega materiala in je zato pomembna za ohranjanje okolja ter trajnostni razvoj.Doctoral thesis considers the possibility of increasing the amount of reclaimed asphalt in the asphalt mixture when adding alternative rejuvenator. During road lifetime the bitumen, which is the most important component of asphalt and dictates its behavior, ages. Therefore, its properties change. With the use of special additives, the so-called rejuvenator, bitumen restores its basic properties. By using rejuvenator, we can increase the proportion of reclaimed asphalt added to the asphalt mixture. Alternative rejuvenator was gained by pyrolysis process from scrap tires. Doctoral thesis consists of three parts. In the first part, different pyrolysis products, generated by varying the time and temperature of the pyrolysis, are briefly presented. Based on their properties, we selected the most appropriate product as an alternative rejuvenator. In the second part the influence of rejuvenator in different concentrations (3 %, 5 %, 10 % and 20 %) to the viscoelastic properties of the non-aged and aged bitumen were examined. Results of the standard mechanical tests, rheological tests and models proved that the alternative rejuvenator revived aged bitumen. The optimal concentration of rejuvenator in the aged bitumen was determined. In the last section, the standard tests for asphalt mixtures have shown that the properties of asphalt mixtures with the addition of reclaimed asphalt and rejuvenator were improved. The addition of rejuvenator increased the proportion of reclaimed asphalt. Reuse of reclaimed asphalt leads to a reduction of waste material and consequently the environment