Modelling the linear viscoelastic rheological properties of bituminous binders

Rheology involves the study and evaluation of the flow and permanent deformation of time-and temperature-dependent materials, such as bitumen, that are stressed through the application of a force. The fundamental rheological properties of bituminous materials including bitumen are normally measured using a dynamic shear rheometer (DSR), from low to high temperatures. DSR is a powerful tool to measure elastic, viscoelastic and viscous properties of binders over a wide range of temperatures and frequencies, provided the tests are conducted in the linear viscoelastic region. Therefore, the study of bitumen rheology is crucial since its reflects the overall performance of a flexible pavement. However, it is well known that the DSR also has limitations, where the measurements are exposed to compliance (testing) errors particularly at low temperatures and/or high frequencies. In addition, conducting laboratory tests are known to be laborious, time consuming and require skilled personnel. Therefore, this research is conducted to elucidate a better understanding of the rheological properties and modelling procedures of bitumens and bituminous binders. Various materials such as unmodified bitumens, polymer-modified bitumens (PMBs) and bitumen-filler mastics, unaged and aged samples, are used in this study. An extensive literature review was undertaken to identify reliable models that can be considered as a valuable alternative tool to describe or fit the rheological properties of bitumen. These properties are commonly presented in terms of complex modulus and phase angle master curves, together with the determination of shift factor values at a particular reference temperature. In general, the complex modulus and phase angle master curves can be modelled using different techniques; nomographs, mathematical equations and mechanical models. However, the nomographs have become obsolete in recent years and tended to be replaced by the two latter models. Those models are able to satisfactorily describe the rheological properties of unmodified bitumen. However, the observations suggest a lack of agreement between measured and predicted rheological properties for binders that contain a phase transition, such as found for highly crystalline bitumen, structured bitumen with high asphaltenes content and highly modified bitumen. An attempt was made to evaluate the validity of several mathematical equations and mechanical element approach using unaged and aged unmodified bitumens and PMBs database. It is observed that the Sigmoidal, Generalised Logistic Sigmoidal, Christensen and Anderson (CA), and Christensen, Anderson and Marasteanu (CAM) Models are able to satisfactorily describe the rheological properties of unmodified bitumens. Nevertheless, they suffer from the same drawbacks where the presence of highly EVA semi-crystalline and SBS elastomeric structures render breakdowns in the complex modulus master curves. Similar discrepancies are observed when one of the mechanical models (the 2S2P1D Model) is used. To construct the master curves, different shifting methods are available. It is found that a numerical shift produced the best fit between measured and modelled data, followed by the Laboratoire Central des Ponts et Chaussées (LCPC) approach, William, Landel and Ferry (WLF), Modified Kaelble, Viscosity Temperature Susceptibility (VTS), Arrhenius and Log-Linear methods. A temperature range from 10 to 75oC is used in this study. It is worth mentioning that most of the methods are empirical and might not be applicable for all materials. Finally, the phase angle master curves must also not be neglected to yield a complete rheological properties of binders. The statistical analysis between measured and modelled data shows that the Fractional Model yielded the best correlation for a temperature range from10 to 75oC, followed by the Al-Qadi and Co-workers, CAM, CA and Kramers-Kronig relationships. An anomaly is observed between measured and descriptive data of the Kramers-Kronig relationship particularly at high frequencies and/or low temperatures. The Fractional Model is not considered suitable for practical purposes due to the high number of coefficients that need to be solved

Modelling the linear viscoelastic rheological properties of bituminous binders

Rheology involves the study and evaluation of the flow and permanent deformation of time-and temperature-dependent materials, such as bitumen, that are stressed through the application of a force. The fundamental rheological properties of bituminous materials including bitumen are normally measured using a dynamic shear rheometer (DSR), from low to high temperatures. DSR is a powerful tool to measure elastic, viscoelastic and viscous properties of binders over a wide range of temperatures and frequencies, provided the tests are conducted in the linear viscoelastic region. Therefore, the study of bitumen rheology is crucial since its reflects the overall performance of a flexible pavement. However, it is well known that the DSR also has limitations, where the measurements are exposed to compliance (testing) errors particularly at low temperatures and/or high frequencies. In addition, conducting laboratory tests are known to be laborious, time consuming and require skilled personnel. Therefore, this research is conducted to elucidate a better understanding of the rheological properties and modelling procedures of bitumens and bituminous binders. Various materials such as unmodified bitumens, polymer-modified bitumens (PMBs) and bitumen-filler mastics, unaged and aged samples, are used in this study. An extensive literature review was undertaken to identify reliable models that can be considered as a valuable alternative tool to describe or fit the rheological properties of bitumen. These properties are commonly presented in terms of complex modulus and phase angle master curves, together with the determination of shift factor values at a particular reference temperature. In general, the complex modulus and phase angle master curves can be modelled using different techniques; nomographs, mathematical equations and mechanical models. However, the nomographs have become obsolete in recent years and tended to be replaced by the two latter models. Those models are able to satisfactorily describe the rheological properties of unmodified bitumen. However, the observations suggest a lack of agreement between measured and predicted rheological properties for binders that contain a phase transition, such as found for highly crystalline bitumen, structured bitumen with high asphaltenes content and highly modified bitumen. An attempt was made to evaluate the validity of several mathematical equations and mechanical element approach using unaged and aged unmodified bitumens and PMBs database. It is observed that the Sigmoidal, Generalised Logistic Sigmoidal, Christensen and Anderson (CA), and Christensen, Anderson and Marasteanu (CAM) Models are able to satisfactorily describe the rheological properties of unmodified bitumens. Nevertheless, they suffer from the same drawbacks where the presence of highly EVA semi-crystalline and SBS elastomeric structures render breakdowns in the complex modulus master curves. Similar discrepancies are observed when one of the mechanical models (the 2S2P1D Model) is used. To construct the master curves, different shifting methods are available. It is found that a numerical shift produced the best fit between measured and modelled data, followed by the Laboratoire Central des Ponts et Chaussées (LCPC) approach, William, Landel and Ferry (WLF), Modified Kaelble, Viscosity Temperature Susceptibility (VTS), Arrhenius and Log-Linear methods. A temperature range from 10 to 75oC is used in this study. It is worth mentioning that most of the methods are empirical and might not be applicable for all materials. Finally, the phase angle master curves must also not be neglected to yield a complete rheological properties of binders. The statistical analysis between measured and modelled data shows that the Fractional Model yielded the best correlation for a temperature range from10 to 75oC, followed by the Al-Qadi and Co-workers, CAM, CA and Kramers-Kronig relationships. An anomaly is observed between measured and descriptive data of the Kramers-Kronig relationship particularly at high frequencies and/or low temperatures. The Fractional Model is not considered suitable for practical purposes due to the high number of coefficients that need to be solved

The effect of preservation maintenance activities in asphalt concrete pavement sustainability

Pavement infrastructure is crucial to quality lifestyle and affluence of society. Since the pavement structure deteriorates after a while, appropriate pavement preservation maintenance is essential to attain a superior performing, safety, and economic pavement network for the users. Nowadays, within a modern society resources and budget are restricted that make it necessary for transportation agencies to discover approaches to use the resources to optimize benefits included in daily operation. Simultaneously, focus on the idea of environmental sustainability has increased substantially. Pavement preservation assists environmental sustainability by preserving energy, raw materials, and mitigating greenhouse gases (GHG) by maintaining good roads in the perfect condition. Thereby, a sustainable pavement maintenance program should look into allocating budget and resources to pavement preservation. Various types of pavement preservation treatments use different levels of energy and produce GHG emissions. Preservation treatments considered in this study included thin hot-mix asphalt (HMA) overlay, chip seal, slurry seal and crack seal. This research states the methodology in sustainable pavement preservation maintenance. Its focus is on quantifying and recognizing which of these pavement preservations practices minimize environmental impacts. As the economic is one of the components in triple bottom-line in sustainability, the next step is focusing on cost-benefit of preservation maintenance activity and comparing by rehabilitation activity. This research aims to persuade pavement organization to apply correct perseverance activity on the right time and proper manner to enhance sustainable development

Introducing Buton Natural Rock Asphalt New Materials for Bitumen Mofification and Soil Stabilization

Abstract:The natural asphalt in the world which can be explored until today is Buton Natural Rock Asphalt (BNRA). The other natural asphalt like Trinidad Lake Asphalt   Based on survey conducted by Directorate General of Mining Ministry of Energy and Mineral Resources Republik of Indonesia, amount of 650 million ton of BNRA are found in Buton island, yet until 92 years since BNRA in Buton Island discover by Hetzel, a Dutch Geolog, only 3.4 ton  that have been explored to be used for road work. This paper reported the using of  BNRA to modify bitumen to improve their properties in order to resist  the high temperature rutting, and to stabilize clay soil, to  improve their strenght. Bitumen penetration grade 80/100 which will be modified was blend by 15 to 65% of BNRA in increments of 5% by weight of bitumen, and to stabilized clay soil, amount of 2% to 8% in increements of 2% BNRA by weight of soil was added. To determine Penetration Index (PI) of neat bitumen and alsobitumen modified with BNRA,  penetration at 250 Celcius and softening point test were conducted. Penetration Index is the parameter to measure the temperature susceptibility of binder. The test results show that ..

Comparative Study of Utilising Neural Network and Response Surface Methodology for Flexible Pavement Maintenance Treatments

The use of Artificial Intelligence (AI) for the prediction of flexible pavement maintenance that is caused by distressing on the surface layer is crucial in the effort to increase the service life span of pavements as well as reduce government expenses. This study aimed to predict flexible pavement maintenance in tropical regions by using an Artificial Neural Network (ANN) and the Response Surface Methodology (RSM) for predicting models for pavement maintenance in the tropical region. However, to predict the performance of the treatment techniques for flexible pavements, we used critical criteria to choose our date from different sources to represent the situation of the current pavement. The effect of the distress condition on the flexible pavement surface performance was one of the criteria considered in our study. The data were chosen in this study for 288 sets of treatment techniques for flexible pavements. The input parameters used for the prediction were severity, density, road function, and Average Daily Traffic (ADT). The finding of regression models in (R2) values for the ANN prediction model is 0.93, while the (R2) values are (RSM) prediction model dependent on the full quadratic is 0.85. The results of two methods were compared for their predictive capabilities in terms of the coefficient of determination (2), the Mean Squared Error (MSE), and the Root Mean Square Error (RMSE), based on the dataset. The results showed that the prediction made utilizing ANN was very relevant to the goal in contrast to that made using the statistical program RSM based on different types of mathematical methods such as full quadratic, pure quadratic, interactions, and linear regression

Wajibkan pita pemantul cahaya terhadap semua kenderaan berat

Pelanggaran membabitkan kenderaan berat seperti treler dengan kenderaan yang lebih kecil seperti kereta selalunya akan berakhir dengan kecederaan parah atau lebih teruk lagi, menyebabkan kematian terhadap penumpang kenderaan lebih kecil

Increase the Strenght of Base and Subbase of Flexible Pavement by adding Fledspar as additive material

The strength and durability of the flexible pavement is highly dependent on the quality of the aggregate material used for base and subbase layers. This is can be understand since  95 percent of the weight-volume of the base and subbase layer is aggregate. Therefore using a good quality and strong base and subbase material is very important. In this paper, which is a report of a reseacrh,  Feldspar is used as stabilizer of base and subbase materlias of flexible pavement. Feldspar  is a group rock-ftant forming tectosilicate minerals that made up about 41% of the earth’s continental crust by weight. 5 to 25% of Feldspar with increment of 5% by weight of the base and also subbase were added. Direct Shear and California Baring Ratio (CBR) test were conducted., beside water content and dry density test. The results of direct shear  test show that cohesion of base and subbase materials decrease from 0,164 kg/cm2 of original base and subbase materials become 0,01 kg/cm2 for base and subbase material after adding with 25% of Feldspar, and angle of inernal friction increase from 47,670 become 49,800. Meanwhile the results of CBR test show that CBR value of base increase from 30% to 86,40%, as well as for subbase increase from 21,50% to 87,30% after adding with 15% of Feldspar. It can be concluded that adding aggregate of base and subbase with Feldspar the strenght improve signicantly, and the influence is the strengthening of the base and subbase layers

A Review of the Utilisation of Recycled Waste Material as an Alternative Modifier in Asphalt Mixtures

The possibility of using waste materials in road construction is of great interest as their utilisation may contribute to reducing the problems of hazard and pollution and conserve natural resources. Thus, there is an urgent need to find a sustainable method for using waste materials as a substitute in the standard asphalt binders. There are several concerns about the physical and chemical properties and mechanical performance of asphalt pavements incorporated with waste material in the effort to reduce permanent deformation of the road surface. This review article presents a brief discussion of the asphalt mixtures modified with waste material, and the recycled materials used as a modifier in the asphalt mixture. The present paper summarises the use of crumb rubber, crushed concrete, steel slag, glass fibre and plastic waste in asphalt mixtures. The use of waste materials as a modifier in asphalt mixture resulted in improved asphalt pavement performance. Results advocate that rubberised asphalt mixture with desired properties can be designed as an additive with a friendly environmental approach in construction materials. The researches that adopted the influence of usage, recycle waste material to improve the performance of the asphalt of the road are still limited compared to other construction fields. Doi: 10.28991/cej-2020-SP(EMCE)-05 Full Text: PD

Evaluating the cooling rate of hot mix asphalt in tropical climate

This paper aims to investigate the environmental effect on cooling rate and to determine the appropriate time available for compaction (TAC) using laboratory tests. This includes the study parameters, namely solar flux, base and ambient temperatures (daytime and night-time paving) and wind velocity, focusing on hot mix asphalt (HMA) asphalt concrete wearing with 14 mm nominal maximum aggregate size (ACW14) mix type for the wearing course and ACB28 mix type for the binder course. Samples were prepared in slab moulds 30.5 cm × 30.5 cm × 5 cm and compacted using a manually operated steel-roller. Readings were taken by averaging the temperature measurements at the middle and surface of the slabs and a temperature of 160 ºC was used as the mixing temperature. A control sample was prepared for each mix type and tested in the laboratory without the influence of wind velocity and solar flux. It was found that the cooling rate of HMA is significantly affected by environmental factors, thus influencing the TAC. The TAC tends to decrease by 15-50% during windy and night conditions but increases by up to 100% during daytime conditions compared to the control samples

Rail-based Public Transport Service Quality and User Satisfaction – A Literature Review

While rail-based public transport is clearly a more advanced and preferable alternative to driving and a way of overcoming traffic congestion and pollution problems, the rate of uptake for rail travel has remained stagnant as a result of various well-known issues such as that commuters either use a more reliable and comfortable alternative to get from A to B and/or that they are not satisfied with the quality of service provided. This study examined the factor of user satisfaction regarding rail-based public transport with the aim of discovering precisely what factors have a significant effect on the user satisfaction and uptake of rail travel. This was approached using both the Delphi approach and a thorough review of the current literature, focusing on a total of nine possible factors affecting passenger satisfaction with rail travel availability of service, accessibility of service, ticket or pass, punctuality, clarity of information, quality of customer service, comfort, safety, and image. Also discussed were 29 extra possible attributes and several measures that were implemented in various countries to increase the service quality. It was concluded that this review will provide valuable information for policymakers, researchers and service providers in terms of specifying the service factors most worth investigating if the quality of this crucial means of transport is to be raised.</p