Evaluating Fly Ash‐Based Geopolymers as a Modifier for Asphalt Binders

Abstract

Severe Canadian winter conditions and growing traffic volumes are vital factors resulting in a reduction of the service life of flexible pavements. Researchers and engineers strived to develop several additives to develop balanced asphalt mixers capable of resisting distresses that caused deterioration of flexible pavements in Canada. In this study, a critical literature review regarding the use of geopolymers and their application in construction materials is provided. Moreover, an experimental matrix of laboratory testing was conducted to study the rheological and microstructural properties of the PG 58-28 asphalt binder, with different percentages (0%, 3%, 6%, and 9%) of geopolymer. The effect of geopolymer-curing time on rheological properties was investigated. Rotational viscometer, dynamic shear rheometer (DSR), and environmental scanning electron microscopy (ESEM) imaging devices were used to compare the performance of control binder with a binder with different percentages of geopolymers. Results indicated that the increase in the geopolymer content and the curing time affect the rheological behavior of the asphalt binder by increasing its viscosity, complex shear modulus, and failure temperature. Samples with higher geopolymer percentage exhibited better performance in terms of rutting resistance. Moreover, an increase in the failure temperature of modified asphalt binder with 9% geopolymer is recorded as 8.58%, 14.2%, and 15.2% for curing times of 2, 7, and 14 days, respectively, compared with virgin asphalt. Furthermore, the nanoparticles appear to be well dispersed in the binder, and increasing the percentage of the geopolymer does not seem to affect the microstructure of the binder. Overall research conclusion is that geopolymer application resulted in a potential enhancement of some of the properties of the asphalt binder.

Fly Ash-Based Geopolymer Building Materials for Green and Sustainable Development

“…However, many fly ash-based geopolymers previously reported in the literature for different purposes and applications could be improved by applying the formulations developed in this study. These formulations could be used to improve the fly ash-based geopolymer coating for fire resistance materials [ 32 ], the immobilization of hazardous substances [ 25 ] and backfilling materials [ 71 ], low micro-filling effect (low porosity) materials [ 24 ], absorbent materials [ 44 ], or asphalt binders [ 43 ].…”

“…Several authors have investigated the synthesis of geopolymers with fly ash for different purposes and applications. For instance, Hamid et al [ 43 ] reported that a geopolymer could potentially enhance some of the properties of the asphalt binder. Wang and Zhao [ 32 ] demonstrated that a dosage of 25 wt% of fly ash or slag was crucial to obtain excellent flame retarding efficiency.…”

Geopolymer utilization in the pavement industry - An overview

“…Industries and companies' sealants [20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35] Heat resistance and fire resistances fiber composites…”

“…Furthermore, at low and high stress levels, modified asphalt binder containing 8% geo fly ash had better rutting resistance than 4 and 12% geopolymer. Also, a study was carried out by Alfaidi et al [32] to evaluate the effects of geopolymer curing on rheological bitumen properties. The outcomes show that the time of curing affects the bitumen rheological performance by increasing its complex shear modulus, temperature, and viscosity.…”

Improving the Properties of Porous Geopolymers Based on TPP Ash and Slag Waste by Adjusting Their Chemical Composition

“…It is known [ 33 , 34 ] that the main problem associated with road construction in the Arctic zone is swelling of the soil due to the freezing of the moisture contained in it. This is due to waterlogging of the soil and long periods with a negative ambient temperature.…”