Quality Of Asphalt Mixture Research Articles

Analysis of Surface Texture of Asphalt Mixture with Sand Circle Method

A road is usually defined as an infrastructure connecting a zone to other zones. As service and safety are essential for vehicle users, any conditions related to the pavement, including surface texture, are considered. The importance of this matter is that many researchers or practitioners are concerned with the quality of asphalt mixtures, whether structural or functional, which affect the safety and security of road users, mainly related to the texture of the pavement surface. This research aims to determine the texture depth (MTD, Mean Texture Depth). The research method used is the circle sand method, which is tested using the Sand Patch tool. The asphalt mixture type uses AC-WC with a composition of 39% coarse aggregate, 54.5% fine aggregate, and 6.5% filler. Optimum Asphalt Content of 6.28% and Density of 2.28 were obtained, and texture depth of 0.549 mm was more significant than 0.45 mm (Bina Marga 2010 revision 3). The conclusion is based on the design composition of the aggregate mix in the AC-WC asphalt mixture, which has a safe texture.

Resilient modulus prediction of nano-silica modified porous asphalt using Finite Element Analysis

Repetitive traffic load is the most important factor influencing porous asphalt (PA) performance. The performance of asphalt is mostly influenced by the loading magnitude of heavy vehicles. In order to improve the service performance of PA under heavy traffic conditions. the decrement of stiffness is one of the failures that occur on the PA which mainly caused by the repeated load from a large number of different types of vehicles which leads to reduce the characteristic of PA in terms of stiffness and durability. Moreover, to enhance the performance of PA against the stiffness reduction an additive material used to increase the strength of the PA called Nano-silica particles. Thus, the aim of the study to investigate the resilient modulus of Nano-silica modified PA and develop a finite element analysis FEA model to predicate the resilient modulus. In this study, three different Nano-silica contents 0%, 2% and 4% by weight of PA mixture were investigated. To achieve this, a finite element model was developed and simulated by using ABAQUS 6.14 software for the PA samples to predict the resilient modulus performance. A comparative study was done among the unmodified and modified PA mixtures considering the resilient modules value. The result showed that Nano-silica is recommended as an additive in PA mixture, as the result of the modified PA mixture with 2% of NS was 4357Mpa while the unmodified was 3001Mpa. Thus, the addition of NS to PA mixture Capable in increasing the strength and quality of asphalt mixture.

Karakteristik Marshall Pada Campuran Asphalt Concrete – Wearing Course (AC-WC) Dengan Penambahan Styrofoam

Styrofoam waste presents the environment issue because it is difficult to decompose. As an effort to recycle this pollutant, styrofoam can be utilized as an additive in asphalt concrete mixture. The use of additives aims to create a flexible pavement layer having good performance and meet the requirements. The purpose of this study is to find out whether the addition of styrofoam can improve the quality of asphalt mixtures, and look for alternative additives that can increase asphalt pavement performance. In this study, researchers used food container styrofoam as an addition and incorforated into Asphalt Concrete Wearing Course (AC-WC) mixture. The styrofoam content was 6.5%; 6.75%; 7% ; 7.25%; and 7.5% of asphalt weight. The optimum asphalt contentused is 5.5%. The value of the optimum stability was 3126,002 kg, found at 7.25% of styrofoam content. The best results of Marshall test was obtained at 6.5% of styrofoam content with stability value 1362,045 kg, VIM value 4,96%, VMA 15,025%, VFA 67,800%, flow 3,44 mm, and MQ 416,338 kg / mm.

Improving accuracy of asphalt content determination by ignition test

Accurate determination of asphalt content and aggregate gradation is critical for controlling quality of asphalt mixtures during construction. Most state specifications require quantitative evaluation of the asphalt content of mixes as a criterion for acceptance. The ignition oven test procedure specified in AASHTO T 308 (Standard method of test for determining the asphalt binder content of Hot Mix Asphalt [HMA] by the ignition method) is required or allowed by most state DOTs for determining the asphalt content and aggregate gradation of asphalt mixtures. The ignition oven test specified in AASHTO T 308 procedure requires the determination of asphalt content correction factors for each asphalt mix and for each ignition oven used. However, in some instances when numerous asphalt mix designs and several ignition ovens are available, correction factors (CFs) are shared between ignition units, even when that practice is not allowed by the standard. There is a need to identify the consequences of sharing correction factors between units/mixes and also to identify testing parameters that affect the measured CFs. By identifying possible causes of variation, the test procedure could be adjusted to make the CFs more consistent between ignition ovens. Also, it should be possible to reduce the amount of difference in CFs between all types of equipment. A study was conducted to assess the variability of ignition oven CFs for different ignition oven unit brands and mixes to better understand the implications of sharing CFs. Twenty-three laboratories used various brands of ovens to test four mixes containing aggregates with varying CFs. The results indicated that CFs were significantly different for the different mixes even when the same unit brand was used. The within-lab and between-lab precision developed in this study suggests that different precision statements are necessary for aggregates with high breakdown potential and that the current precision included in AASHTO T 308 was likely developed for low weight loss aggregate making it unacceptable to use for aggregates with higher CFs. It was also found that the addition of lime caused no significant difference in the measured asphalt content when the CF was correctly measured. However, it was cautioned that a change in amount of lime during mixture production would affect the measured asphalt content. In addition, ways to minimise variability in asphalt CF were evaluated. It was determined that ignition tests conducted at lower temperature (427°C) proved to be effective in reducing the variability in measured asphalt content since the lower temperature reduced the asphalt correction factors for asphalt mixes.

Temperature field of asphalt mixture based on microwave heating

ABSTRACTTo improve regeneration quality of asphalt mixture through microwave heating, the main parameters that influence temperature field distribution is explored by analysing horn antenna radiation electromagnetic field and heat conduction model of the asphalt mixture. Seven types of horn antenna with different aperture plane sizes and lengths were used for simulation. The results are as follows: (1) the more similar the lengths of the aperture plane's long and short sides are, the more average temperature field distribution is, and (2) the antenna lengths in H and E planes have minimal influence on temperature field distribution. The microwave heating experiments with different powers revealed that after improving the microwave power, the speed of elevated temperature becomes more obvious, but the temperature field distribution becomes less uniform. A comparison of continuous microwave heating and intermittent microwave heating experiments shows that the intermittent heating method could improve the uniformity of temperature distribution, but energy loss is more than that of continuous microwave heating. The findings have a guiding significance for the choice of structure perfection of horn antenna and heating method, which finally could improve the regeneration quality of the asphalt mixture.

Use of Crumb Rubber as an Additive in Asphalt Concrete Mixture

As the rapidly growing number of vehicles in Indonesia, the waste of tire rubber becomes a major environmental concern. The use of crumb rubber, which is the recycled tire rubber, as an additive in hot mix asphalt mixture is considered as a sustainable construction method. The purpose of this study was to investigate the effect of adding crumb rubber to asphalt mixture using wet process. The laboratory hot mix asphalt design tests were done by Marshall Method procedure. In this study, two different crumb rubber contents (1% and 2% by weight of asphalt mixture) and two different crumb rubber sizes (#40 and #80) were investigated. A comparative study was done among the unmodified and modified asphalt concrete mixtures considering the Marshall Stability value and the volumetric properties. The results showed that crumb rubber is recommended as an additive in asphalt mixture, as all the test results are within the standard requirements. The addition of crumb rubber tended to increase the strength and quality of asphalt mixture. However, it should be more concern about durability of asphalt mixture because of the lower asphalt content in crumb rubber modified asphalt mixture.

A study on characteristics evaluation to control quality of asphalt mixture using X-ray CT

The aim of this paper is to propose X-ray computed tomography (CT) as a new evaluation method of asphalt mixtures. To achieve this aim, all sections of three benchmark and three core samples of porous asphalt mixture at an expressway were subjected to X-ray CT scanning, internal characteristics were analysed, and a minimum slice number was decided. As a result of internal characteristics, the internal density indicated a tendency to increase by a rise in the height in the core samples, whereas the internal density indicated a tendency to become larger at the centre than at the top or bottom in the benchmark samples. With slice number examination, a trustable average density will be obtained by CT scanning if five slices at least are scanned at equal interval.

Design of Micro-Computer Controlling System for Batch Asphalt Mixing Equipment in Measurement and Gradation

The paper illustrates the design theory and method of micro-computer controlling system for batch asphalt mixing equipment in measurement and gradation. Then combined with the practical application, the paper introduces the solution of factors of affecting the quality of asphalt mixture.

Influence of Mixing Equipment on Asphalt Mixture Segregation

In order to improve mixing quality of asphalt mixture, a method of theoretical analysis and test was used to analyze the effects of negative pressure of drying drum, geometric parameters of mixer and aggregate variation ratio in hot aggregate bins on the segregation of asphalt mixture. Reasonable measures of controlling segregation in the mixing process were given out. Research results indicate that stable negative pressure of drying drum reduce the temperature segregation of asphalt mixture by controlling temperature undulation of hot aggregate and reasonable arrangement of mixing blades cut down material segregation of asphalt mixture with adequate mixing. That isn’t all, delivery proportion of the aggregate in hot aggregate bins and mesh size of vibrating sieve, properly selected according to the gradation of cold aggregate, improve quality and efficiency of asphalt mixture with lower aggregate variation in hot aggregate bins.

LONG-TERM PERFORMANCE OF RECYCLED ASPHALT MIXTURES IN COLD, SNOWY REGIONS

Research was performed to investigate the changes in the quality of asphalt mixtures that were repeatedly recycled in a cold, snowy region. Asphalt binders with penetration values of 80 to 100 and aggregates recycled from asphalt were used in studying the properties of asphalt binders and repeatedly recycled asphalt mixtures. The focus was on their various properties in the low-temperature range. Test pieces made from asphalt that had been repeatedly recycled and degraded to a penetration value of approximately 20, showed wide variations in chemical and physical properties. The results demonstrate that bringing recycled aggregates to the same quality as new materials requires more than just adjusting the penetration value of the aggregates by adding recycled admixture.