Laboratory evaluation of rheological behavior of binder and performance of stone matrix asphalt (SMA) mixtures containing zycotherm nanotechnology, sasobit, and rheofalt warm mixture additives

Abstract

In recent years, using Stone matrix asphalt (SMA) has gained a lot of attention due to its high performance in rutting and low cost of pavement maintenance, however it consumes high energy like other hot mixtures during production. Also, as Warm mix asphalt (WMA) has several advantages like environmental concerns, many countriesshowed interest in using this new technology. One of the shortcomings of WMA is moisture sensitivity, which is investigated by several researchers. However, the interaction between various factors on moisture resistance of SMA mixture have not been investigated. Also, the addition of warm additives may affect other properties of mixtures. So in current work, the effect of WMA additives on rheological properties of binder and performance of mixtures were investigated. The present research aimed to evaluate the effect of three different gradations (9.5 mm, 12.5 mm, 19 mm), three warm additives (Sasobit, Rheofalt, Zycotherm) with various contents on water damage resistance and performance of warm SMA mixtures. The rheological behavior of original and warm modified bitumens was investigated by performing viscosity, dynamic shear rheometer (DSR), Linear Amplitude Sweep (LAS), Multiple Stress Creep Recovery (MSCR) tests. Performance properties of mixtures were investigated through four-point beam fatigue (FPB), resilient modulus, Indirect tensile strength (ITS), dynamic creep, and wheel track tests. The moisture sensitivity of modified mixtures was assessed through four different methods, such as: Resilient Modulus Ratio, Fracture Energy Ratio, Tensile Strength Ratio, and Texas boiling test. The LAS test results indicated that bitumen containing 1% Sasobit has the highest fatigue life in low strain levels, while in high strain levels, the Zycotherm modified binder has the highest fatigue life. The MSCR test outcomes revealed that binder containing 3% Sasobit has the highest rutting resistance. The outcomes revealed that the addition of warm additives enhanced moisture resistance of samples. Among warm modified mixtures, Zycotherm modified specimens had the highest resistance to water susceptibility. The results indicated that the addition of warm additives enhanced performance properties of mixtures. Among warm additives, 3% Sasobit has the highest effect on enhancing the rutting and fatigue behavior of mixtures.