A review on the surface activation of waste crumb rubber with chemical reagents to improve its compatibility with bitumen

Description

A review on the surface activation of waste crumb rubber with chemical reagents to improve its compatibility with bitumen

Nie Tian*, Piergiorgio Tataranni, Cesare Sangiorgi

Department of Civil, Chemical, Environmental, and Materials Engineering, University of Bologna

Via Umberto Terracini, 28, 40131 Bologna, Italy

nie.tian2@unibo.it, piergiorg.tataranni2@unibo.it, cesare.sangiorgi4@unibo.it

ABSTRACT: Incorporating waste crumb rubber (WCR) in asphalt pavements facilitates rubber recycling while enhancing pavement performance. However, more in the dry than wet process, inadequate compatibility between WCR and bitumen inevitably causes issues like surface raveling and mixture delamination, thus compromising pavement durability. To address this, surface treatments aim to modify WCR’s physical and chemical properties. Despite the complexity and ambiguous classification of existing methods, chemical reagent-based treatments stand out for clear definition and proven effectiveness. This study critically discusses most of these treatments, including oxidation, acidification, alkalization, grafting and functionalization, devulcanization, decomposition, pre-swelling, and pre-coating. The findings facilitate the development of innovative and hybrid treatments while fostering further reflection on balancing processing efficiency and practical necessity in the sustainable recycling of WCR in asphalt pavements.

KEYWORDS: rubber, recycling, surface treatment, chemical reagents, compatibility, bitumen.