Effects of tetraethyl orthosilicate on rheological behaviors of crumb rubber modified asphalt

The purpose of this work is to study the rheology, fatigue properties and physical changes of crumb rubber modified asphalt (CRMA) after pretreatment of rubber crumbs with tetraethyl orthosilicate (TEOS). Six weight ratios of TEOS to crumb rubber, 0%, 15%, 20%, 25%, 35%, and 50%, were chosen to prepare modified crumb rubber (CR) and use it to prepare CRMA. The effects of TEOS on the physical properties of CRMA were analyzed through softening point, penetration and ductility tests. Mechanical tests including multiple stress creep and recovery (MSCR) test, temperature sweep test, and linear amplitude sweep (LAS) test were conducted to evaluate rheological properties and fatigue resistance. The results show that TEOS addition can effectively improve the physical properties, rheological properties and high temperature stability of CRMA. However, the excessive addition of TEOS can decrease rheological properties and fatigue life of rubber-modified asphalt. The results of temperature scanning test and MSCR test show that CRMA has the best G* and delta under the condition that TEOS content is 25% of CR mass; and it has optimal non-recoverable creep compliance (J(nr)) and percentage of re-covery (R%). LAS test results indicate that CRMA has better fatigue life when TEOS content is 25% of CR.