Karol J. Kowalski

Long-Term Monitoring of Noise and Frictional Properties of Three Pavements: Dense-Graded Asphalt, Stone Matrix Asphalt, and Porous Friction Course

Three highway test sections were monitored for friction, texture, and noise properties over a period of 4 years. The monitored highways were constructed from dense-graded asphalt (DGA), stone matrix asphalt (SMA), and porous friction course (PFC) mixes. The PFC was intended to reduce tire–pavement noise. It was found that the PFC and SMA pavements exhibited comparable frictional properties (international friction index and skid number), which were significantly higher than those observed in the DGA section. It also was found that the PFC section was the quietest and that SMA was louder than DGA. In general, all three sections performed well, and no failures were noticed in any of the monitored pavements during the course of this study.

Quality assessment of bituminous binders based on the viscoelastic properties: Polish experience

Construction of modern and durable bituminous pavements requires high quality bituminous binder, aggregates and additives. The main objective of this paper was to analyse and compare viscoelastic properties of unmodified and polymer modified bitumens produced in Poland, Europe, in order to assess their quality. In this paper there are presented results of bituminous binder European classification tests (penetration, softening point and Fraass breaking point) as well as rheological test results conducted over a wide range of temperatures. In addition, image analysis of the microstructure of selected polymer modified bitumens is also presented. Based on the analysis it was concluded that although bituminous binders complies with European specification requirements, they are significantly different in terms of their rheological properties. It was found that regardless of binder producer, bituminous binder within the same hardness group exhibit different low and high temperature properties.

Identification of Laboratory Technique to Optimize Superpave HMA Surface Friction Characteristics

This report summarizes an investigation into various options for polishing, testing and analyzing pavement surface frictional properties in the laboratory. Devices were sought that could assess the effects of both microtexture and macrotexture of hot mix asphalt (HMA) surfaces in the laboratory and the field. The investigation consisted of a detailed literature review and consultations with users of existing devices for polishing and testing pavement materials. The recommended devices include the Dynamic Friction Tester (DFT) and the Circular Texture Meter (CTM). This study is the first phase of a planned three-phase research program to examine the frictional characteristics of Superpave HMA mixtures. A plan for continuing with Phase II of the project, using the recommended devices and funded by the Indiana and Iowa Departments of Transportation, is also outlined.

Object-Oriented Mutation Applied in Common Intermediate Language Programs Originated from C#

Application of object-oriented mutation operators in C# programs using a parser-based tool can be precise but requires compilation of mutants. Mutations can be introduced faster directly to the Common Intermediate Language of. NET. It can be simple for traditional mutation operators but more complicated for the object-oriented ones. We propose the reconstruction of complex object-oriented faults on the intermediate language level. The approach was tested in the ILMutator tool implementing few object-oriented mutation operators in the intermediate code derived from compiled C# programs. Exemplary mutation and performance results are given and compared to results of the parser-based mutation tool CREAM.

Effects of Sand Characteristics and Fly Ash Contents on Properties of Flowable Fill

This research examines the effects of sand characteristics and fly ash contents on fresh properties and on the unconfined compressive strength of flowable fill mixtures. Additionally, this research investigates the flowability of wet and dry sands and the influence of fly ash addition on this property using a number of sand sources and various levels of fly ash addition. It was found that adding fly ash into dry or wet sand substantially influenced its flowability. In addition, it was found that the flowability of sand-fly ash mixtures was influenced by such sand properties as fineness modulus and uncompacted air void content. Similarly, other flowable fill properties, such as bleeding, subsidence, penetration resistance, and unconfined compressive strength, were observed to vary with the sand property and the amount of fly ash added into the mixture.

Rubber modified bitumen

Abstract: Among several methods of waste rubber recycling, the reuse of crumb rubber for bitumen modification deserves special attention. The chapter includes a review of methods for bitumen modification with crumb rubber, a discussion of the types of bitumen–rubber interactions, and a description of the properties of rubber–modified bitumen and asphalt–rubber mixtures. It also summarizes the benefits from the use of asphalt rubber mixtures in road construction.

Towards Understanding the Polymerization Process in Bitumen Bio-Fluxes

Bitumen is a commonly used material for road construction. According to environmental regulations, vegetable-based materials are applied for binder modification. Fluxed road bitumen containing a bio-flux oxidation product increases the consistency over time. The efficiency of crosslinking depends on the number of double bonds and their position in the aliphatic chain of fatty acid. The main goal of this paper was to examine the structural changes taking place during hardening bitumen with bio-flux additives. Two types of road bitumens fluxed with two different oxidized methyl esters of rapeseed oil were used in this study. Various chemical and rheological tests were applied for the fluxed-bitumen at different stages of oxygen exposure. The oxidation of rapeseed oil methyl ester reduced the iodine amount by about 10%–30%. Hardening of the fluxed bitumen generally results in an increase of the resins content and a reduction of the aromatics and asphaltenes. In the temperature range of 0 °C to 40 °C, bio-flux results with a much higher increase in the phase angle than in temperatures above 40 °C in the bitumen binder. The increase in the proportion of the viscous component in the low and medium binder temperature is favorable due to the potential improvement of the fatigue resistance of the asphalt mixture with such binders.

Evaluation of Reclaimed Asphalt Pavement for Surface Mixtures

The Indiana Department of Transportation has successfully used Reclaimed Asphalt Pavement (RAP) for decades because of its economic and environmental benefits. Because of uncertainties regarding the types of aggregates contained in RAP and their resulting frictional properties, however, INDOT has until recently disallowed the use of RAP in asphalt surface mixtures. In addition, the hardened asphalt binder in the RAP could potentially increase the occurrence of thermal cracking. This research was conducted to explore the effects on RAP with poor or unknown aggregate qualities to establish maximum allowable RAP contents to provide adequate friction. The effects of RAP on thermal cracking were then investigated at the potential allowable RAP contents. Laboratory testing showed that the addition of poor quality RAP materials did impact the frictional properties and cracking resistance of the mixtures, but that lower amounts of RAP had little effect. The frictional performance of the laboratory fabricated and field sampled RAP materials was acceptable at contents of 25% but may be questionable at 40%. Field friction testing was also conducted on existing roadways with RAP to explore their field frictional performance. Several low volume roadways and one experimental interstate project were tested. The field results showed acceptable performance after 3 to 5 years of low volume traffic at RAP contents of 15‐25% and after more than 10 years of interstate traffic with 15% RAP. The low temperature testing showed an increased susceptibility to thermal cracking as the RAP content increased but the change in critical cracking temperature was relatively small at the 25% RAP level. At 40% RAP without a change in the virgin binder grade, the critical cracking temperature was about 6°C warmer than the control mixture. This finding supports the need for a binder grade change for RAP contents greater than 25%, as indicated in other research and as required by the current INDOT specifications.

Modified Ignition Oven Test Procedure for Determination of Binder Content in Hot Mix Asphalt Containing Dolomite Aggregate

The binder content of hot mix asphalt (HMA) is most commonly determined either by solvent extraction or ignition oven (IO) methods. Generally, the IO method has worked well with various HMA mixtures except those containing certain types of high mass loss (decomposing) aggregates, especially dolomite. For these aggregates, the high temperatures experienced during the ignition process initiate chemical changes within the aggregate particles, which result in variable mass losses. This, in turn, causes difficulties in calculating a consistent correction factor and determining a repeatable binder content. This paper presents a modified IO binder content determination method, which involves lowering the test temperature to 427°C and reducing the sample mass by half. In addition, only the bottom material basket of the typical IO test setup is used to avoid errors in the results due to temperature differentials that develop when, upon ignition, mixture from the lower basket starts heating the mixture in the upper basket. The proposed method was successfully verified by using six different plant-produced mixtures.

Long Term Performance of a Porous Friction Course

In 2003, the Indiana Department of Transportation and the Federal Highway Administration allowed a test section of Porous Friction Course (PFC) to be placed on I74 east of Indianapolis. The design, construction and early performance of that surface were compared to an adjacent Stone Matrix Asphalt (SMA) surface and a conventional Superpave HMA surface in a report prepared for the Institute for Safe, Quiet and Durable Highways. The early performance indicated that the PFC offered several advantages over the SMA and the conventional surfaces, including reduced tire/pavement noise, high friction and surface texture, and reduced splash and spray. There was a concern, however, that porous surfaces can lose their porosity, and therefore their performance advantages, over time. Consequently, the project summarized in this report was planned to continue monitoring the performance of the PFC and the comparison surfaces in order to investigate the durability of the porous surface over a five-year period (after construction). After five years under traffic, there have indeed been some changes in these properties. Most of the changes, however, took place quickly as the asphalt binder film coating the exposed aggregate particles was worn off by traffic. Since then, the changes have been relatively minor. The PFC section is still significantly quieter than the adjacent SMA section to which it has been compared. The PFC has retained most of its texture and is still providing good friction levels. Both the PFC and the SMA are still in very good condition with little distress and have higher friction levels than a section of dense graded asphalt constructed with similar materials that has also been evaluated for the duration of the study.