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Asphalt mixture modification with rubberised material frequently results in improved characteristics and extended service life in actual application. This research characterised the synergistic consequences of rubber modifiers (crumb rubber powder (CRP) and natural rubber latex (NRL)) and wax-based admixtures (Tough Fix Hyper (TFH)) on the performance of the asphalt mixture from the fracture energy and laboratory fracture resistance perspectives. Semicircular bending (SCB) and indirect tensile strength (ITS) tests were conducted to assess the fracture properties of the asphalt mixture samples. To prepare asphalt mixture samples, the wet method was utilised. Higher CRP levels resulted in greater strength and a longer time to attain peak force for both control and mixtures containing wax admixture, as determined by SCB. The interaction between the higher CRP or NRL content and the TFH additive enhanced the fracture resistance, indicating that the components are highly compatible. The 10L + TFH additive produced the highest fraction of energy, indicating a more significant improvement than the counterpart mixes containing the CRP modifier. In addition, incorporation of the CRP and NRL increased the fracture plastic zone (FPZ), resulting in increased fracture toughness. Therefore, the gradient of fracture toughness and fracture energy in the asphalt mix depends on the rubber type, content, and TFH. Although the higher CRP, NRL, and TFH improve the fracture energy and cracking resistance, they increase the crack initiation and propagation velocities, whereby the high bitumen stiffness makes the mixture more brittle than the control mixture. Caution should be exercised when selecting the content of rubber modifier and TFH for the asphalt pavements in low-temperature service. Also, there is a direct interconnection between fracture resistance and fracture energy in the mixtures containing CRP, NRL, and TFH. Such correlations can be used as the premise of predictive micro- and macro-models to evaluate mixture performance in terms of fracture resistance. [ABSTRACT FROM AUTHOR]

Asphalt pavement structures in countries with tropical climates are prone to experience distress, mainly due to water related damage. This study aims to evaluate the effects of ZycoTherm on the behaviour of natural rubber latex (NRL) modified asphalt binders. The morphology of the modified asphalt binders was also investigated. Two different percentages of NRL were incorporated in this study, at 3% and 6% respectively based on the weight of the asphalt binder. The modified asphalt binders (with or without ZycoTherm) were analysed based on softening point, penetration value, rotational viscosity, complex modulus, phase angle, rutting potential, and torsional recovery (TR). Subsequently, the spreadability of NRL in the asphalt binder was observed using a polarising optical microscope. The results indicate that the addition of NRL improved the performance of the asphalt binder in terms of its G*/sinδ parameter. An agglomerated network of mixed microstructures was formed in the modified asphalt binder matrix irrespective of the aging condition. Meanwhile, the morphology structure of virgin and short term-aged binders prepared with ZycoTherm indicates uniform dispersed network monographs. From the modified asphalt binder test results, it can be deduced that asphalt binders prepared with ZycoTherm exhibit superior resistance towards rutting potential. [ABSTRACT FROM AUTHOR]

Moisture damage is one of the most frequent damages that occurs on asphalt pavements. The application of rubberized materials for asphalt is widely acceptable due to cost saving and environmentally friendly. The purpose of this study is to assess the performance of rubberized asphalt mixtures containing wax-based admixture, namely Tough Fix Hyper (TFH), in terms of moisture sensitivity and hazardous compound leaching potential. The moisture absorption, chemical immersion, and boiling water tests were used to assess the resistance to moisture damage on aggregate-binder bonding characteristics. Following that, the trend of moisture sensitivity was evaluated through an image analysis procedure. To simulate the environmental impact of leaching, the toxicity characterization leaching procedure (TCLP) test was adopted. The results showed that interaction between the crumb rubber or latex with TFH decreases the stripping value of the mixes significantly based on the chemical immersion test. Furthermore, the image analysis of the samples subjected to boiling water conditioning showed that pixels of asphalt samples without TFH, ranging from 524,949 to 472,346, decrease from 520,870 to 289,070, indicating that the asphalt remained coated area improved by 67.70–91.39%. The analysis of the leachate test revealed that the heavy metals, including arsenic (As), nickel (Ni), copper (Cu), chromium (Cr), vanadium (V), and cadmium (Cd), were not detected. However, zinc (Zn) was detected in the modified mixture, ranging from 0.05 to 0.114 mg/L, which lies within the allowable norm. In conclusion, the incorporation of crumb rubber and TFH in asphalt mixtures poses no environmental risk. • The performance of rubberized asphalt mixtures containing wax-based admixture was studied. • The moisture sensitivity was evaluated through an image analysis procedure. • The environmental impact of leaching was evaluated using TCLP test. • Samples subjected to boiling water indicated that the asphalt remained coated area improved within 68–92%. • The outcomes of the leachate test revealed that the incorporation of crumb rubber and wax admixture has no environmental risk. [ABSTRACT FROM AUTHOR]

• Effects of source and content of reclaimed asphalt pavement were characterised. • Two new parameters were proposed to analyse trend and variations of dynamic modulus of asphalt concrete. • Effects of the reclaimed materials on activation energy of asphalt binder were evaluated. • The trend of relative dynamic modulus depends on source and content at frequency and temperature sweeps. • There are some correlations between the activation energy of binders and dynamic modulus of mixes. The effects of the reclaimed asphalt pavement (RAP) source and content on the dynamic modulus (E*) of hot mix asphalt concrete were characterized. Two parameters were proposed: the non-dimensional dynamic modulus-temperature index (∇ E T *) and non-dimensional dynamic modulus-frequency index (∇ E fr *). Parameter ∇ E fr * indicates the increase of relative E* per unit percent RAP from different sources during frequency and temperature sweeps, while ∇ E T * characterizes the reduction of relative E* per 1 °C temperature increase. An analysis of the results showed that ∇ E T * of RAP mixes were 6.80% to 12% higher than those of the control samples, indicating less temperature susceptibility. Furthermore, an analysis of ∇ E fr * trends showed temperature independency at higher temperature ranges. In addition, the results showed that the activation energy (AE) of the mixes was 1.51 MJ/mol/K to 9.86 MJ/mol/K higher than that of the control samples (without RAP), which depends on the RAP content and source. Moreover, E* linearly increases as AE increases. In conclusion, the increase of intermolecular forces owing to the higher AE in the blended binders increased the mix stiffness, which resulted in a higher E* in mixes containing RAP. [ABSTRACT FROM AUTHOR]

This paper discusses the engineering properties of waste glass (WG), including its structural and environmental performance, as an alternative material for the construction of various types of paving systems, including asphalt, concrete, and block pavements. As a first step, an overview of the asphalt, cement, and glass manufacturing industries is provided. Then, a large volume of data is analyzed from various sources in the literature. Particular emphasis is given to laboratory studies of the structural performance and durability of WG. Additionally, the effect of WG on the field performance of the pavements is discussed. The sustainability of the pavements is also evaluated in terms of energy consumption, greenhouse gas emissions, safety, and the heat island phenomenon. In conclusion, the use of WG can improve various phases of pavement life and structure by enhancing the structural performance, durability, environmental friendliness, and aesthetic features of pavements. [ABSTRACT FROM AUTHOR]

This literature review paper presents the effects of a chemical warm mix additive, named Rediset on the rheological properties of asphalt binders, laboratory performance of asphalt mixtures, field behaviour of constructed road sections, energy consumption and air pollution, physicochemical properties of asphalt binders and behaviour of asphalt mortar. The rheological effects of Rediset on asphalt binder were evaluated from the viewpoint of very high temperature properties (viscosity of asphalt binder and workability of asphalt mixtures), high temperature properties (rutting resistance of asphalt binders and mixtures), intermediate temperature (fatigue behaviour) and also low temperature cracking properties. Other topics such as the mechanisms of temperature reduction by Rediset, storage stability of Rediset modified binders, moisture susceptibility, mix design issues, volumetric properties and economic benefits were also investigated. The information reported in this paper will help decision makers to appropriately select, apply and evaluate this warm additive type. In addition, researchers can identify gaps in existing knowledge for future research. [ABSTRACT FROM PUBLISHER]

In this study, the rheological properties and activation energy (AE) of unaged and aged asphalts blended with different percentages of binder, recovered from three reclaimed asphalt pavement (RAP) sources, were investigated. Superpave asphalt binder tests were used to evaluate the effects of the recovered asphalt binder source and content. The results indicated that the addition of recovered binder from each source increased the viscosity, , and . The increase in viscosity per 1% recovered binder was evaluated using non-dimensional viscosity index (). In addition, the increase in and per 1% recovered binder were investigated using relative Superpave rutting gradient (RSRG) and relative gradient (RG) factors, respectively. The results indicated that the , RSRG, and RG depended on recovered binder source, content, aging, and test temperature. The interpretation of the AE results depended on the physical phase of the asphalt blends, irrespective of the recovered binder source and content. The AE increased when the physical phases of the asphalt blends were in liquid and semiliquid (high phase angle) states over the range of temperatures tested compared with the control asphalt binder. However, the AE decreased when the physical phase of the asphalt blend samples was solid (low phase angle). [ABSTRACT FROM AUTHOR]