Volumetric Characteristics of HRS-WC Mixed Using Petroleum Bitumen Grade 60/70 as Binder

This study aims to determine the volumetric values consisting of VIM, VMA and VFB on the binder layer mixture using HRS-WC gradation using petroleum bitumen as a binder. The method used in this research is experimental method in laboratory. In this study, variations of asphalt content used were 5.5%, 6.0%, 6.5%, 7.0% dan 7.5%. These variations were obtained from the calculation of effective asphalt level of 5.9%. The results show that the VIM values decreases along with the increase of bitumen content used. VIM values obtained were 6.69%, 5.82%, 5.18%, 4.42% and 3.34%, respectively. The VMA values obtained were 18.12%, 18.38%, 18.84%, 19.21% and 19.30% for each bitumen content. Besides that, the value of VFB is also taken into account and the values obtained for each quality of bitumen content are 63.10%, 68.41%, 72.57%, 76.99% and 82.71%.

Investigation of Factors Causing Nonuniformity in Luminescence Lifetime of Fast-Responding Pressure-Sensitive Paints

Factors that cause nonuniformity in the luminescence lifetime of pressure-sensitive paints (PSPs) were investigated. The lifetime imaging method of PSP does not theoretically require wind-off reference images. Therefore, it can improve measurement accuracy because it can eliminate errors caused by the deformation or movement of the model during the measurement. However, it is reported that the luminescence lifetime of PSP is not uniform on the model, even under uniform conditions of pressure and temperature. Therefore, reference images are used to compensate for the nonuniformity of the luminescence lifetime, which significantly diminishes the advantages of the lifetime imaging method. In particular, fast-responding PSPs show considerable variation in luminescence lifetime compared to conventional polymer-based PSPs. Therefore, this study investigated and discussed the factors causing the nonuniformity of the luminescence lifetime, such as the luminophore solvent, luminophore concentrations, binder thickness, and spraying conditions. The results obtained suggest that the nonuniformity of the luminophore distribution in the binder caused by the various factors mentioned above during the coating process is closely related to the nonuniformity of the luminescence lifetime. For example, when the thickness of the binder became thinner than 8 μm, the fast-responding PSPs showed a tendency to vary significantly in the luminescence lifetime. In addition, it was found that the luminescence lifetime of fast-responding PSP could be changed in the depth direction of the binder depending on the coating conditions. Therefore, it is important to distribute the luminophore uniformly in the binder layer to create PSPs with a more uniform luminescence lifetime distribution.

Effects of Crushed Glass Waste as a Fine Aggregate on Properties of Hot Asphalt Mixture

The recycling of waste requires large areas; besides recycling wastes to their origin is often economically and environmentally costly. Glass is considered as a solid waste that is difficult to dispose of; it doesn't degrade nor burn. Since glass is a silicic substance with similar properties to aggregates, it can be recycled in asphalt mixtures. This research aims to determine optimum binder content (OBC) of conventional hot asphalt mixture (HMA), (control mixture), and investigate the effect of crushed glass waste (CGW), on its properties. In this work, several percentages of CGW (10%, 15%, 20%, and 25%) have been used as a partial substitution for the weight of fraction size 2.36-0.075mm of natural aggregate to prepare glass-contained asphalt mixtures and compare their properties with the control mixture. Mix design by Marshall method was used, and the properties according to Iraqi standards (SORB/R9,2003), for binder layer, were found, as well as conducting of Retained Marshall stability (RMS), indirect tensile strength (IDT), and tensile strength ratio (TSR), tests on mixtures, as performance tests. The results showed that the OBC of the control mixture was 5% wt., and the Marshall stability and flow values of glass-contained asphalt mixtures were oscillating around the values of the control mixture. The air voids, voids in mineral aggregate, and bulk density were reduced regularly as CGW increased. Also, it was observed from the results that the glass-contained mixtures have good performance properties. However, all results conformed to the standards (SORB/R9, 2003). So, the incorporation of CGW in HMA for the binder layer is feasible.

Life Cycle Assessment of Sustainable Asphalt Pavement Solutions Involving Recycled Aggregates and Polymers

The pursuit of sustainability in the field of road asphalt pavements calls for effective decision-making strategies, referring to both the technical and environmental sustainability of the solutions. This study aims to compare the life cycle impacts of several pavement solution alternatives involving, in the binder and base layers, some eco-designed, hot- and cold-produced asphalt mixtures made up of recycled aggregates in substitution for natural filler and commercial recycled polymer pellets for dry mixture modification. The first step focused on the technical and environmental compatibility assessment of the construction and demolition waste (CDW), jet grouting waste (JGW), fly ash (FA), and reclaimed asphalt pavement (RAP). Then, three non-traditional mixtures were designed for the binder layer and three for the base layer and characterized in terms of the stiffness modulus. Asphalt pavement design allowed for the definition of the functional units of Life Cycle Assessment (LCA), which was applied to all of the pavement configurations under analysis in a “from cradle to grave” approach. The LCA results showed that the best performance was reached for the solutions involving a cold, in-place recycled mixture made up of RAP and JGW in the base layer, which lowered all the impact category indicators by 31% on average compared to those of the traditional pavement solution. Further considerations highlighted that the combination of a cold base layer with a hot asphalt mixture made up of CDW or FA in the binder layer also maximized the service life of the pavement solution, providing the best synergistic effect.

Study Enhancing the Rutting of Flexible Pavement by Adding Selected Polymers into Asphalt Mixes

Rutting in flexible pavement is one of the main permanent deformation which appears in most Iraqi roads owing to high temperature and the increase in axial excessive heavy trucks load, these combined conditions cause a major impact on the road performance. The polymers used as additives to improve the properties of asphalt and, that leads to achieve high quality asphalt mixture. This humble research focused on finding the suitable treatment for such issue by using SBS and HDPE. Whereas 5 percent for each polymer was used (2%, 4%, 6%, 8% and 10%) by weight of total mix. A different percentage of polymers were used in order to achieve the best additive percent which was proved to be (8% HDPE, 6% SBS) for wearing (III A) layer and (6% HDPE, 2% SBS) for binder layer. As well as the results showed that using the optimum percent of additives for each layer of asphaltic mixture and test it as one specimen formed from two layers, has decreased the rutting percent by (72%, 65%) for (HDPE, SBS) respectively for each type of additives at (40ºC).

Evaluation of the Characteristics and Coating Film Structure of Polymer/Ceramic Pressure-Sensitive Paint

Polymer/ceramic pressure-sensitive paint (PC-PSP), which incorporates a high percentage of particles in the binder layer, is proposed in order to improve the characteristics of PSP. The procedure for embedding particles into the binder layer was modified. In the conventional procedure, dye is adsorbed onto a polymer/ceramic coating film (denoted herein as a dye-adsorbed (D-adsorbed) PSP). In the new procedure, the mixture of a dye and particles is adsorbed onto a polymer coating film (denoted herein as the particle/dye-adsorbed (PD-adsorbed) PSP). The effect of particle mass content on PSP characteristics was investigated. In addition, the effect of solvent on PSP characteristics and film structure were evaluated for the PD-adsorbed PSP. As a result, the difference in the PSP characteristics between the two types of PSP was clarified. Although surface roughness and time response increase with increased mass content of particles for both D- and PD-adsorbed PSPs, the critical pigment volume concentration (CPVC) for the PD-adsorbed PSP is smaller than that of the D-adsorbed PSP (88 wt% and 93 wt%, respectively). The PD-adsorbed PSP has a higher frequency response comparing with the D-adsorbed PSP while maintaining the same surface roughness. Observation by scanning electron microscope showed that the CPVC of the PC-PSP is governed primarily by surface structure. The coating film structure can be roughly classified into two states depending on the particle mass content. One is a state in which the coating film consisted of two layers: a lower particle-rich layer and an upper polymer-rich layer. This type of structure was observed in the PD-adsorbed PSP as well as in the D-adsorbed PSP. In the other state, polymer and particles are homogeneously distributed in the film, and pores are formed. This difference in the coating structure results in a change in the time response.

The influence of the particle size of the filler on the detachment from the binder under composite fuel tension

During operation, the fuel in case-bonded charges stretches, and at the “filler-binder” boundary tear stresses occur. In highly filled compositions, the thickness of the binder layer between the filler particles is minimal and the probability of achieving critical stress values with particle detachment is high. The structure of polyfraction fuel is modeled and the influence of the particle size of the filler on the tear stresses under static tensile load is analyzed

Microstructure and Erosion Properties of HVOF Sprayed Cermet Coatings via Different Feedstock Powders

In the present study, Cr3C2-NiCr and WC-Co coatings have been deposited using high velocity oxygen-fuel (HVOF) spray technology from five available powders with various bonding phase content or manufacturing process. The microstructure of coatings was observed by scanning electron microscopy (SEM). Microhardness and erosion performance of the coatings were studied. The influence of powder characteristics on the microstructure and erosion performance of coatings was also investigated. The results indicated that an independent bonding phase distributed in the feedstock powder can effectively improve the erosion resistance of Cr3C2-NiCr coatings although the microhardness of the coatings may be lower. Deformation of the free NiCr binder layer in the coating is probably to prevent nucleation and propagation of cracks, which may result in improving the erosion resistance of the coating. Nano WC-Co coatings reached lower erosion resistance than micro WC-Co coatings due to the higher porosity and lower microhardness of nano WC-Co coatings.