Polymer Bitumen Research Articles

The Use of Polymer Stabilised Earth Foundations for Rammed Earth Construction

This paper presents a case study as part of a Professional Doctorate research project discussing an ecological approach to housing in South Africa, where polymer stabilised earth foundations have been used to support single story rammed earth walls, in a house in South Africa. Rammed earth was chosen as a construction method for its low embodied energy and thermal mass characteristics. The subsurface strata upon which the house was built comprised of clayey, gravely, sandy soils that have resulted as a result of decomposition of granitic rocks. In order to ensure solid founding conditions the foundations were excavated to a depth of one and a half metres before the excavated material was stabilised and backfilled. The material was stabilised to 600mm below top of floor level with 2% Portland cement and above that with a 5% polymer bitumen mixture reinforced with horizontal steel reinforcing rods. This foundation avoids the use of reinforced concrete and as a result a significantly smaller carbon footprint, while fulfilling the functional requirements of supporting the building and preventing rising damp. The polymer has, as it major component is bitumen emulsion, provided a waterproof layer. Rammed earth walls of 500mm thickness were constructed on the foundation up to 4.2 meters in height and initial observations suggest that the foundations are satisfactory with no settlement or cracking detected.

Modification of cast asphalt mixtures by Fischer-Tropsch paraffin waxes and various polymers

The modification of polymer–bitumen binders by finely crystalline paraffin waxes produced by the Fischer-Tropsch gasification of coal is considered. Such modification is widely used in highway construction in the United States and Europe. Recently, paraffin waxes (FT paraffins) have become available in Russia. Their distinctive structure proves useful in improving the rheological properties of bitumen. To predict the properties of cast asphalt mixtures, research is conducted not only on the final cast asphalt samples but also on the modified binders based on styrene-butadiene-styrene polymers and Fischer-Tropsch paraffins. The Fischer-Tropsch paraffins may be used to improve the properties of cast asphalt mixtures. The best option identified in this research is PBV 40 binder containing BND 60/90 bitumen, 5.5% LG 501; 3% FNET, and 1.5% Sasobit.

Indoor Study on Road Performance of Macromolecule Polymer Bitumen Waterproof and Cohesive Layer (PCMA)

The quality of waterproof and cohesive layer determines the service life of bridge deck pavement. Conventional modified bitumen bonding layer exits some deficiencies that its shear strength is low, construction process is complexity and it need to spread gravel. In order to solve the problem, the new type of waterproof and cohesive layer called PCMA is developed and researched. Through the indoor test study on road performance of the PCMA, the results shows that PCMAs shear strength, drawing stress and fatigue life are significantly higher than other waterproof and cohesive layer. It is especially suitable for hot and humid regions.

Analysis of Rheological State of SBS Modified Bitumens Based on Viscosity Measurements

Abstract Each bitumen has a slightly different group composition, thus bitumen modification with the SBS copolymer gives slightly different results in each case. Both in the industry and construction practice there is still no simple method available which would allow the evaluation of the impact of SBS content and the group composition of bitumen on the structural and rheological properties of the polymer bitumen mix. The article presents the results of the dynamic viscosity tests of three bitumen types. Based on the analysis of the results obtained, it was found that changes in the rheological properties caused by SBS additive are characteristic for each of the bitumens tested and their chemical and group composition. They are also proportionate to the amount of the modifier added. In order to have a possibility to measure this impact, three coefficients rheologically characterizing polymer and bitumen mixes were applied.

Sustainability Assessment of Bitumen with Polyethylene as Polymer

Now a day's increment in percentage of waste material due to excessive use of polyethylene in daily use products has become a great problem. Most of the waste materials are of types which are non- biodegradable. These materials require difficult and challenging methods to dispose safely and in underdeveloped countries like Pakistan it is even a bigger problem of concern. Also the continuous increase in number of vehicles emphasizes on need of sustainable infrastructure of roads with better quality and engineering design. Grinded plastic is used as polymer in Bitumen in this research by 0% ,0.5 %, 1%, 1.5 % and 2 % .The properties evaluated are Fire point ,Flash point, softening point and penetration of Bitumen. Regardless of the replacement ratio, Bitumen as a polymer had a satisfactory performance. I. INTRODUCTION The continuous increase in number of vehicles emphasizes on need of sustainable infrastructure of roads. Specially in under developed countries like Pakistan where road networks don't get the proper maintenance due to lack of effective machinery and funds , there is a major need of better infrastructure of roads which needs less maintenance and serve the purpose. To abandon the process of deterioration of roads many methods may prove useful, e.g., increasing budget for alimony, better roadway structure, choosing more appropriate components and state of the art technologies used for construction. The pavement structure of roads is basically flexible in Pakistan and its reliability is affected by many important factors, e.g., environmental conditions, chemical and physical properties of materials in mix (additive, binder and aggregate) and the ratio in which these materials are used. The performance of mix (bitumen) can be noticeably enhanced by changing the additive part in the mix. There are currently many additives being used, but polymers are of great interest and a field of research these days. Another interesting use of polymers is in asphalt concrete amalgamates which in return produces an aggregate covering stuff. These coverings will prove helpful in increasing the surface roughness and hence, show more resistance against wear and more closely meet the modern world requirements. From the last five decades the population all over the world has increased enormously, and to meet the gap of supply and demand rapid increase in number of industries has become a necessity and as an end result production of by products, mainly waste materials became a great problem. Most of the waste materials are of type which are non-degradable and non-recyclable e.g., Tires, tubes, some form of plastics, ash, slag (Steel and blast furnace), harmful chemicals and toxic resins. These materials require difficult and challenging methods to dispose safety and in underdeveloped countries like Pakistan it is even a bigger problem of concern. There comes a great need to find out some useful purpose of these thin polythene wrappers as they are abundant as waste materials. If so happens that they find their application, they can be easily collected and separated from other undesirable trash by interested organizations rather to litter in cans or open places.

Developing of Effective Multipurpose Polymer-Bitumen Compositions

We researched and developed effective polymer bitumen composites for hermetic of deformities seals of concrete and asphalts roads, bridges, aerodrome and airfields used in hot climate conditions and high lands.

Influence of the morphology of thermoplastic elastomers on the properties of bitumen composites

Bitumen properties may be successfully modified if the polymeric modifiers have the ability to control the elastic and plastic properties within wide temperature ranges of −30/−40°C to +45/+60°C. The article presents a study on the ability of two thermoplastic elastomers, thermoplastic block co-polymer styrene–styrene butadiene (SBS) and the co-polymer ethylene–vinyl acetate (EVA), to be used in obtaining polymer bitumen composites with controlled properties. The elastic and plastic properties of the bitumen composites can be more easily controlled if these composites are modified with SBS. This thermoplastic elastomer is characterized by an optimum ratio between soft domains of amorphous polybutadiene and rigid ones of those represented by the thermoplastic blocks of polystyrene.

Compounding of oxidized and nonoxidized products of petroleum processing - a promising method of improving the properties of road bitumens

The need for constantly increasing the quality of road bitumen binders is substantiated. It is shown that the use of the principle of compounding both in preparing initial materials for the production of road bitumens and in obtaining commercial bitumens by mixing oxide products with high-boiling components permits increasing the quality of bitumen binders as a result of directed regulation of their chemical composition. It is established that a mixture of oxidized bitumen and high-boiling products of petroleum processing can be an optimal petroleum base for obtaining high-quality bitumen polymer compounds.

Dimensional stability of waterproofing bituminous sheets used in low slope roofs

Lap joints between waterproofing bituminous sheets, applied in either single or multiple layers, are one of the most critical areas of roofs, especially when the waterproofing systems comprise only a single sheet. In fact, the way how lap joints are executed is highly associated with the occurrence of anomalies in such systems. With this regard, the dimensional stability of the sheets is one of their most important characteristics, as it that can strongly influence the performance of the lap joints and the details on roof upstands. In this context, with the aim of contributing to improve the understanding of this characteristic of bituminous sheets, the present paper presents results of an experimental study on the dimensional changes suffered by bituminous sheets when subjected to temperature variations. Different types of traditional and non-traditional sheets, with various types of bituminous mixtures (oxidised bitumen and atactic polypropylene (APP) and styrene–butadiene–styrene (SBS) modified bitumen) and reinforcements (polyester, glass fibre and polyethylene) were tested according to EN 1107-1 standard. For most of the sheets, the isolated reinforcements were also subjected to dimensional stability tests in order to evaluate their influence on the overall performance of the waterproofing layer. The results of these experimental investigations confirm that sheets with polyester reinforcement are much less stable than sheets reinforced with glass fibre. In addition, it was concluded that the influence of the type of polymer–bitumen is negligible when compared to the influence of the type of reinforcement – in general, the dimensional stability of the sheets is worse than that of the corresponding reinforcement. Finally, it is shown that the dimensional stability performance of similar products produced by different manufacturers is similar, both for the isolated reinforcements and for the waterproofing sheets.

Portuguese Irrigation Canals: Lining Solutions, Anomalies, and Rehabilitation

AbstractIrrigation canals are primary hydraulic infrastructures from an agricultural point of view, and their performance is highly dependent on the efficiency and durability of their coatings. This paper presents the main conclusions of a survey undertaken in Portugal, which concluded that in most situations, the following technologies are used: concrete cast on site, precast concrete slabs, and prefabricated membranes (polymer bitumen or synthetic). These linings may manifest various pathologies with significant consequences on the amount of water lost as a result of lack of watertightness. These defects are classified by lining solution, and their main causes identified. Finally, an exhaustive set of recommendations and rehabilitation techniques are described to minimize water leakage from the canals.

Interaction and Molecular Weight Distribution Behavior in Polymer Blends of Styrene-Butadiene-Rubber and Bitumen

Styrene-Butadiene-Rubber (SBR) modified bitumen had improved properties in softening points, ductility, and aging resistance. It is due to variation of molecular weight (MW) and molecular weight distribution (MWD) of the product made during the blending between SBR and bitumen. Gel permeation chromatography (GPC) analytical results indicated interaction in polymer blends that bitumen macromolecular chain biting and chemical forces as well as intermolecular recombination formed new bitumen polymer blends.

Effect of processing temperature on the bitumen/MDI-PEG reactivity

Reactive polymers are lately gaining acceptance to give added value to a residue of the crude oil refining process such as bitumen. The resulting material should display enhanced mechanical properties to be considered for advanced applications in construction. In the present paper, we report the effect of processing temperature on the reaction between bitumen compounds and an isocyanate-based reactive polymer, synthesized by reaction of polymeric MDI (4,4′-diphenylmethane diisocyanate) with a low molecular weight polyethylene-glycol (PEG). Rheokinetics experiments, viscosity measurements at 60 °C, atomic force microscopy (AFM) characterization, thin layer chromatography (TLC-FID) analysis and thermogravimetric studies (TGA) were performed on the reactive polymer and on samples of MDI-PEG modified bitumen containing 2 wt.% of the polymer. Results showed the existence of an optimum processing temperature arisen as a consequence of opposite effects: microstructural availability for the formation of a polymer–bitumen network, reaction ability and polymer thermal degradation. Consequently, this study aims to serve as a guideline for the refining and asphalt industries facing the stage of selecting the optimum processing parameters.

Process rheokinetics and microstructure of recycled EVA/LDPE-modified bitumen

Knowledge of the kinetics of the manufacturing process of polymer–bitumen blends is of great interest because it provides information on the behaviour of the binder at different stages of the mixing operation, which is useful for the establishment of the optimum processing conditions, involving temperature and operation time. The purpose of this research was to study the evolution of the rheological properties and microstructure of a polymer-modified bitumen during its processing. A 60/70-penetration grade bitumen and recycled EVA/LDPE were mixed under different processing conditions. Measurements of the evolution of viscosity with time, at different temperatures and agitation speeds, were carried out with an experimental device known as ‘rheomixer’, that is, a helical ribbon impeller inside a mixing vessel coupled with the transducer and motor of a conventional rheometer. Under the experimental conditions selected (within the laminar region, Re<10), temperature is the most important processing variable. Hence, low agitation speeds and a processing temperature of around 180°C should be chosen for bitumen modification with the polymer used.

STUDY FOR MATERIAL CHARACTERIZATION AND MANUFACTURE METHOD OF THE HIGH VISCOUS MODIFIED ASPHALT USED FOR POROUS PAVEMENT

In recently, high viscous modified asphalts have been formulated that is various polymers and additives in rich contents compared with normal high viscous modified asphalt. They have been used for porous asphalt applied in severe condition areas such as heavy duty intersection, cold regions and steel plate deck bridges and also they have been used for porous asphalt with small top sized aggregates and/or high voids which are often adopted in road constructions with performance-relating specifications. This research work studied for quality guarantee periods for high viscous modified asphalt using the indoor manufacturing/storage pilot equipments which had better correlation with those of the factory. And more practical evaluation method for bitumen polymer dispersion morphology was proposed.

Rheological properties of styrene butadiene styrene polymer modified road bitumens ☆

The use of polymers for the modification of bitumen in road paving applications has been growing rapidly over the last decade as government authorities and paving contractors seek to improve road life in the face of increased traffic. Currently, the most commonly used polymer for bitumen modification is the elastomer styrene butadiene styrene (SBS) followed by other polymers such as styrene butadiene rubber, ethylene vinyl acetate and polyethylene. This paper describes the polymer modification of two penetration grade bitumens with SBS. Six polymer modified bitumens (PMBs) were produced by mixing the bitumens from two crude oil sources with a linear SBS copolymer at three polymer contents. The rheological characteristics of the SBS PMBs were analysed by means of conventional as well as dynamic mechanical analysis using a dynamic shear rheometer (DSR). The results of the investigation indicate that the degree of SBS modification is a function of bitumen source, bitumen–polymer compatibility and polymer concentration, with the higher polymer concentrations in a high aromatic content bitumen producing a highly elastic network which increases the viscosity, complex modulus and elastic response of the PMB, particularly at high service temperatures. However, ageing of the SBS PMBs tends to result in a reduction of the molecular size of the SBS copolymer with a decrease in the elastic response of the modified road bitumen.

Rheological evaluation of ethylene vinyl acetate polymer modified bitumens

The morphological, thermal and fundamental rheological characteristics of ethylene vinyl acetate (EVA) copolymer modified bitumens are studied in this paper. Nine plastomeric EVA polymer modified bitumens (PMBs) have been produced by laboratory mixing bitumen from three sources with an EVA copolymer at three polymer contents. The morphology, thermal properties and rheological characteristics of the EVA PMBs have been analysed using fluorescent microscopy, differential scanning calorometry and dynamic mechanical analysis using a dynamic shear rheometer, respectively. The results of the investigation indicate that EVA polymer modification increases binder stiffness and elasticity at high service temperatures and low loading frequencies with the degree of modification being a function of bitumen source, bitumen–polymer compatibility and polymer concentration. Filler type modification is evident at low temperatures, temperatures above the melting temperature of the semi-crystalline EVA copolymer and for those modified binders that do not exhibit a dominant polymer network.

An attempt at engineering the bulk properties of blends of a bitumen with polymers

AbstractWe have taken blends of a bitumen with three homopolymers that produce systems softer than the bitumen, and to each have added small quantities of different semicrystalline polyolefins. The intention is to discover whether these will form an extensive network system within a blend with a low Tg in which crystallites create the cross‐links, as may happen with the isotactic polypropylene present in some atactic polypropylene systems. Such thermoplastic cross‐links might provide a useful feature for certain uses, such as in built‐up roofing membranes. These were found only within one blend based upon the polybutadiene, in two blends based upon chlorinated polyethylene, but in none based on the Lycra®, whose blends with LLDPEs and the HDPE flowed below the crystal melting temperature. The E′′ plots indicate the presence of many loss processes within the blends at low temperatures: the tan δ plots show other processes active up to 200°C within the soft matter. The behavior we discovered suggests that the properties of binary polymer blends are not associated solely with the components, but that, when the material is stiff or after heating, certain polymer—bitumen interactions may also be significant, and are sensitive to slight differences of structure between LLDPEs, even when present at the 3.4% level. © 2002 Wiley Periodicals, Inc. Adv Polym Techn 21: 275–286, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/adv.10032

Stress Relaxation in Polymer-Modified Bitumens

The efficiency of BNK-40/180 bitumen modification with a blended thermoelastoplast and its components is studied by measuring the kinetics of the stress relaxation in melts. Asphaltene agglomerates are disclosed to be the main kinetic units of the stress relaxation in bitumens and bitumen–polymer compositions. The efficiency of bitumen modification with polymers is mainly affected by the solubility of the latter in the malthene fraction and their adsorption on asphaltenes. The experiments performed made it possible to estimate the behavior of modified bitumens at low shear rates corresponding to the extreme conditions of their use.

Viscosity of polymer-bitumen binders

Polymer–bitumen binders for the highway engineering were obtained by the addition of a ternary ethylene–propylene rubber to a bitumen. The addition of a vulcanizing agent to a polymer–bitumen composition caused the structuring of the system through cross-linking of rubber molecules in the bitumen matrix that was confirmed by the study of structural viscosity of the polymer–bitumen compositions, as well as molecular mobility by the methods of NMR-relaxation and pulsed field gradient NMR-relaxation (self-diffusion).

BRITTLENESS OF ORGANIC BINDERS AFTER REPEATED TENSION AT NEGATIVE TEMPERATURES

ABSTRACT Under real conditions of road pavement operation the films of organic binders are subjected to repeated tensile deformations, in particular, at negative temperatures. In the paper, an attempt to use Fraas apparatus not only for determining the brittleness temperature of binders but also for estimating their long-term strengths at negative temperatures under conditions of repeated tension at bending has been realized. One has investigated bitumens of BND 40/60; 60/90; 90/130 grades and polymer bitumen binders on their base with 2.0; 3.5; 5.0% of block copolymer of SBS type and of DST-30R-01 grade and 20% of plasticizer-industrial oil. For all specimens the Fraas brittleness temperature and also the temperature at which a binder layer on the metal plate cannot withstand 200 cycles of bending tension without developing a large crack have been determined. For bitumens this temperature is 5 to 7°C higher than the corresponding britteness temperature. A polymer bitumen layer withstands 200 cycles of bending tension at the temperature which is 1°C higher than the corresponding Fraas brittleness temperature. The Fraas temperature of the pre-loaded specimen decreases in specific cases by 20°C. It is shown that the crack resistance of polymer bitumen binders is significantly higher and that of bitumens is lower than it is expected according to the procedure of determining the Fraas brittleness temperature. The crack resistanse of the polymer-bitumen binder specimens in the process of loading at negative temperatures increases.