An overview of moisture damage performance tests on asphalt mixtures

This paper presents a review of moisture damage performance tests on asphalt mixtures. The moisture damage remains to be a detriment to the durability of the Hot Mix Asphalt (HMA) pavement. Moisture damage can be defined in forms of adhesive failure between bitumen and aggregates and cohesive failure within bitumen. Aggregate mineralogy, bitumen characteristics and anti-stripping additive dominantly influence the performance of asphalt mixtures towards moisture damage alongside construction methods, climate and traffic loading. Various laboratory test methods have been developed to quantify the moisture damage performance of asphalt mixtures by resembles the action in the field, including qualitative test such as Boiling Water Test (ASTM D3625) and quantitative tests such as Modified Lottman Test (AASHTO T283). Both of these tests consist of two phases, which are conditioning and evaluation phase. This paper will review the effectiveness of the selected available tests based on various asphalt mixtures materials. Generally, this study indicates that asphalt mixtures consisted of limestone aggregates, modified bitumen and addition of anti-stripping additives will provide more resistant towards moisture damage

The usage of recycled glass in hot mix asphalt: A review

Waste material has been defined as any type of material by-product of human or industrial activity that has no residual value. The elimination of waste glass in landfills become a serious challenging task which several countries look out on it on all sides of the world. Reusing of glass waste for road construction is a sustainable solution to environmental and ecological problems. Reusing of glass waste will reduce the construction cost of pavement, reduce the landfill cost. This study has done to review the overall performance of asphalt concrete blend, in which several exceptional combinations of aggregate is replaced with various proportions of crashed glass. This review is discussed some main properties of asphalt mixture, such as stability and flow. The results shown that the stability was higher than that of the glass waste samples and decreasing as the glass waste increasing. In general, the research displays that using glass waste in asphalt mixture is acceptable

Effect of viscoelastic behaviour of cellulose oil palm fiber (COPF) modified 60-70 asphalt binder for deterioration for roads and highways

This paper dealt with the viscoelastic behaviour of Cellulose Oil Palm Fiber (COPF) modified 60-70 penetration grade asphalt binder for the deterioration of roads. The main objective of this study is to investigate the effect of various COPF content on the physical and rheological properties of penetration grade 60-70 asphalt binder. Laboratory tests performed comprises of viscosity, penetration, softening point, short & long term ageing and complex shear modulus (G*). The COPF was blended in 0.2, 0.4, 0.6, 0.8 and 1.0% by weight of asphalt binder including 0% as control. The COPF modified asphalt binder showed an increasing viscosity and softening point with increase of COPF content, whereas penetration decreases as the COPF increases for the binder. The complex shear modulus (G*), rutting factor (G*/sin δ) and fatigue factor (G*sin δ) show significant improvement for the modified samples compared to unmodified samples. The results indicated that the COPF modified asphalt binder has high potential to resist permanent (rutting) deformation and fatigue cracking than the unmodified sample

Two-stage cultivation strategy for simultaneous increases in growth rate and lipid content of microalgae: a review

The depletion of fossil fuels and the search for novel sustainable energy sources are challenges faced by countries throughout the world over the past few decades. Microalgae have received considerable interest as new oil sources for biofuel production. However, the enhancement of the lipid content in microalgae strains without decreasing the growth rate is a prerequisite for improving the economic viability of microalgae-derived biofuel production. The implementation of an appropriate cultivation strategy can increase both lipid accumulation and biomass production. One of the most-often suggested strategies is the cultivation of microalgae through two-stage cultivation strategy (TSCS). This paper aims to recapitulate the findings of recent studies and achievements in improving the lipid productivity and economic feasibility of TSCS. This article starts by highlighting different types of TSCS based on various stimuli. Afterwards, the most noteworthy culture parameters, including growth stage and initial cell density, are addressed. The existing experimental results show that lipid productivity can be enhanced by optimizing stress factor(s) and engineering processes. Moreover, it is reported that the modification or elimination of the pre-harvesting phase (which can be done by upgrading technical aspects and/or via stress induction strategies) can promote the economic feasibility of TSCSs