Evaluation of Reclaimed Asphalt Mixtures Modified by Nanoclay Powder on Moisture Damage

Recycling asphalt is a significant stage in pavement industry, yet it can be unfavorable to the durability of the recycled mix due to the loss of binder charachteristics, thus the mixture will be weaker to the external factors like moisture. This study aims to evaluate the influence of nanoclay montmorillonite k10 powder (MMT) on Marshall’s characteristics and moisture resistance in Reclaimed Asphalt Pavement (RAP) mixtures. Three percentages of rejuvenated RAP were used, 30%, 40%, and 50% of the total mixture, these percentages were modified with 0%, 1%, 3%, and 5% nanoclay (MMT) of the neat binder’s weight. Asphalt Cement AC(85-100) was used to rejuvenate the RAP. The Marshall test was conducted on modified RAP to detect the effect on the Marshall stability and flow and air void, indirect tensile strength tests (ITS) were also conducted before and after nanoclay powder addition to compare and assess the resistance of moisture to rejuvenated RAP mixtures. The results of the laboratory tests have shown that the use of 5% nanoclay in the regenerated RAP mixes offers superior performance than without it, where it enhanced stability by 15%, reduced flow by 14.3%, and increased moisture damage resistance by 3.66% all for 50% RAP mixtures.

Impact Of Traffic Characteristics and Pavement Surface Condition on Noise Level for Rigid Pavement

The proper design of a road’s surface layer can result in pavements that are not only better in terms of ride comfort and safety, but also in terms of noise reduction. The use of low-noise pavements may be an effective measure to reduce the acoustic pollution generated by road traffic This study aims to consider the effect of changed pavement features on the noise level. Tire/pavement noise is a major contributor to traffic noise at highway speeds. The effects of pavement properties, including air-void content, gradation properties, roughness, texture, pavement surface condition are major contributors to traffic noise at highway speeds. As the overall texture and IRI, increase noise levels. The results showed that greater air void content decreases the level of high-frequency noise.

The Flow-Structure Couplings of Fluidelastic Instability and the Effect of Frequency Detuning in Triangular Tube Bundles Subjected to a Two-Phase Flow

For decades, fluidelastic instability (FEI) has been known to cause dramatic mechanical failures in tube bundles. Therefore, it has been extensively studied to mitigate its catastrophic consequences. Most of these studies were conducted in controlled experiments where significant simplifications to the geometry and flow conditions were utilized. One of these simplifications is the assumption that all tubes have the same dynamic characteristics. However, in steam generators with U-bend tube configuration, the natural frequencies of tubes are nonuniform due to manufacturing tolerances and tubes' curvature in the U-bend region. Thus, this investigation aims to understand the rule of frequency variation (detuning) on FEI in two-phase flow. This includes investigating the effect of detuning on transverse and streamwise FEI for air-water mixture flow. The role of FEI damping and stiffness couplings was investigated over the entire range of air void fraction, or equivalently, the mass-damping parameter. It was found that frequency detuning could elevate the stability threshold caused by either coupling at high air void fraction in the case of transverse FEI. Furthermore, the frequency detuning had a marginal effect on the stability threshold for water flow. It was observed that the mass-damping parameter has a critical impact on FEI under detuning conditions.

Effect of Various Types of Superplasticisers on Consistency, Viscosity, Structure and Long-Term Strength of Geopolymer Products

This article presents the results of research on the effect of plasticisers made based on four different compounds—melamine (M), naphthalene (NF), acrylic polymers (AP) and polycarboxylic ethers (PC)—added to the tested mixes in the amount of 2% of the fly ash (FA). The influence of superplasticisers (SPs) on the consistency of the fresh concrete was investigated using a flow table and a penetrometer, and the air voids content was determined by means of a porosimeter. Additionally, the influence of plasticisers on the viscosity of the paste was investigated using a rheometer. Hardened mortar that matured under two different conditions was also tested at elevated and room temperatures. The tested properties were 7-, 28- and 90-days compressive strength and internal microstructure viewed under a microscope. NF had the greatest viscosity-reducing effect while it increased the air void volume in the mix at the same time. The highest early and late strengths were obtained after curing in elevated temperature samples with an acrylic-polymer-based superplasticiser. However, the increased curing temperature of the samples only influenced the early strength results. Its effect was not visible after 90 days. The AP addition also had a significant impact on improving the consistency of the mixture. The addition of plasticisers did not affect the microstructure of the specimens.

Effect of percent air voids content on the deformation properties of the asphalt mixture

Asphalt mixture is a building material with many advantages. Therefore, it is most used in road construction. If the asphalt mixture is laid with the prescribed technology, it can withstand load effects to long-term. It is necessary to take samples that will be subjected to laboratory measurements. There are several laboratory test, for example measurement thickness of the asphalt mixture layers, the aggregate fraction, quantity of binder in the mixture, determination of air void in asphalt mixture layers. Samples taken directly from the construction site are subjected to laboratory tests. This article focuses on one of the laboratory tests and it is determination of air void in asphalt mixture layers. The determination of air void in asphalt mixture layers is test in detail, because this effect has influence on the deformation properties of asphalt mixture layers. Therefore, it was necessary to model of air void in asphalt mixture layers with different degrees air void. On this purpose was use program Abaqus. The results were plotted. This graphs showed that increasing the air void in asphalt mixture layers has effect on the expansion of deformations. This can lead to faster pavement degradation.

Substitution of Fly Ash as Mineral Filler in Wearing Course of Hot Mix Asphalt

Fly Ash (FA) is one of the sustainable materials to substitute Ordinary Portland Cement (OPC) was found commercialized in construction field but the usage in HMA pavement is limited. Thus, this study is important to promote FA as a sustainable filler instead of using OPC to reduce greenhouse gases. The primary aim is to investigate the Marshall Stability of HMA that incorporating of OPC and FA as filler. In addition, Optimum Bitumen Content (OBC) determination also conducted in this study. Marshall Stability test was conducted based on ASTM 2006 for both mixtures. The parameters gained from the test are the stability, flow, air void in mix (VIM), void filled bitumen (VFB) and stiffness being used to OBC. The OBC for HMA with OPC filler obtained is 5.06% meanwhile for HMA with FA is 4.79%. All Marshall Parameters was complied with of Malaysia Public Work Department (PWD) Standard for both mixtures. The HMA with FA filler give better results for all parameters. Based on OBC percentage, usage of asphalt binder was reduced at 0.29%. Thus, it was more economical if using FA compared with OPC as a filler. Furthermore, HMA with FA filler have better stability and strength as well as lesser deformation with HMA with OPC filler. For the overall, FA have huge potential in substituting other mineral filler to produce better quality of asphalt pavement.