Viscoelastic and viscoelastoplastic characterization of pavement materials by means of simple testing and simple equipment is of great concern to pavement technologists. Another area of great concern is the replacement of premium aggregates by local materials after improving the engineering properties of the local materials. Such replacement is for the avoidance of the high costs of hauling the well-graded aggregates whose resources are also being depleted. These two research areas were combined in this study. A uniformly graded dune sand which is abundant in desert-like areas was upgraded with hydrated lime and stabilized with asphalt to improve its engineering properties. By variation of some of the mix design variables, a mix that complied with Marshall and Hveem stability criteria was produced. The effect of lime on the engineering properties of the mix was studied, and substantial improvements due to the addition of lime were observed. A mix that contained 10% Type S lime was found to have engineering properties that were comparable with those of conventional asphaltic concrete. Also, the effect of lime on the thermorheological, thermal, and elastic properties of bituminous mixes in general was studied. In addition to complying with the above-mentioned stability criteria, the lime-sand-asphalt mix was characterized by creep compliance, over wide ranges of time and temperature, so that the mix is available for thickness design by both the empirical and the theoretical methods of pavement design. New, simple equipment by which repeated as well as constant load creep tests can be easily performed was introduced and used to develop a viscoelastic-plastic constitutive law of the designed lime-sand-asphalt mix. Both the equipment and the testing are simple and gave repeatable measurements. Models for the elastic, plastic, viscoelastic and viscoplastic responses of the designed mix were derived from measurements taken by this equipment and by using computerized regression analysis techniques. Generalized models for the viscoelastic strain during the N-th loading and the N-th recovery period were developed. A FORTRAN computer program was written for computing the four strain components mentioned above separately, and for computing the total strain component for large numbers of load repetitions.

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M. Tech. Civil Engineering. / The purpose of this study is to evaluate the effect of an increase in stone size and volume on asphalt. This will be limited to asphalt surfacing with a viewpoint to the coal haulage industry.

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Thesis (MScIng)--University of Stellenbosch, 2004. / ENGLISH ABSTRACT: This thesis covers the factors affecting compactibility of hot mix asphalt including gradation, filler/binder ratios, binder types, binder content, polymer modification, temperature, volumetric properties etc. The study is not limited to compactibility as the property measured, but also on the influence of these factors on the mix’s capacity to resist permanent deformation or rutting. An experimental design was used with a variety of the above factors being included. Laboratory analysis of the mixes as well as accelerated pavement testing of different mix types using the one-third scale Model Mobile Load Simulator (MMLS3) was carried out. The analysis assists in identification of the factors that influence both compactibility and rut resistance, those influencing the one but not the other, and those factors having no significant influence. The compactibility of the mixes has been analysed in terms of voids in the mix at a specific binder content and compaction level. Special consideration was given to the characterisation of the filler and filler/binder system of some mixes. It was found that gradation of a mix has a significant influence on compaction and the rutting performance. High filler/binder ratios were found to be the critical factors influencing the compactibility of the wearing course mixes investigated, but based on the limited tests performed, the reduction of the filler/binder ratios for improved compactibility did not significantly increase rutting under accelerated pavement testing. As expected, the binder type has a significant influence on the rutting resistance as well as compactibility. In addition, an increase in binder content facilitated compaction, but decreased rutting resistance. Polymer modification considerably improved the rutting resistance of a standard mix under the same loading conditions. Although some modifiers may improve rutting resistance, it requires higher compaction temperatures. The addition of the antistripping agent Gripper L decreased the rutting, aggregate stripping and also the rate of rutting of the Quartzite LAMBS mix that result from the stripping failuremechanism. Low densities can lead to considerable rutting and moisture damage, especially when a moisture susceptible aggregate is used. In terms of compactibility as evaluated with the Superpave Gyratory Compactor, it appears that there exists a temperature window in which compaction can be achieved, but in terms of rutting; even a small deviation in temperature can influence rutting results significantly. The control of the temperature during testing is critical if meaningful comparisons between different mixes with regard to rutting performance are to be made. Linear elastic and finite element analysis has been performed to ascertain whether different specimen geometries would influence the stress distribution within the specimen, and subsequently the rutting results. It was found that the geometry of test specimens has an influence on the stress distribution within the specimens, which can influence the permanent deformation results. The briquette specimens tested in the laboratory also yielded higher rutting results for the same mix tested in the field. It is therefore important to use specimens that are most representative of field conditions / AFRIKAANSE OPSOMMING: Hierdie tesis ondersoek die faktore wat ’n invloed het op die kompakteerbaarheid van warm asfalt. Faktore sluit in onder andere gradering, vulstof/bindstof verhouding, tipe bindstof, bindstof inhoud, polimeer modifisering, temperatuuur, volumetriese eienskappe, ens. Hierdie studie is nie net beperk tot kompakteerbaarheid as ‘n gemete eienskap nie, maar ook die invloed van hierdie faktore op die mengsel se vermoë om weerstand te bied teen permanente deformasie of spoorvorming. ’n Eksperimentele ontwerp wat ’n verskeidenheid van bogenoemde faktore insluit is gebruik. Laboratorium analise van die mengsels asook versnelde plaveisel toetse van die verskillende tipe mengsels is gedoen met die een-derde skaal Mobiele Lassimuleerder (MMLS3). Die analise help met die identifikasie van die faktore wat beide kompakteerbaarheid en spoorvorming beïnvloed, asook dié wat slegs die een maar nie die ander beïnvloed, en ook die faktore wat geen beduidende invloed het nie. Die kompakteerbaarheid is geëvalueer in terme van die hol ruimtes in die mengsel by ’n bepaalde bindstof inhoud en verdigtingsgraad. Spesiale aandag is geskenk aan die eienskappe van die vulstof en vulstof/bindstof wisselwerking van die mengsels. Die gradering van ’n mengsel het ’n beduidende invloed op kompakteerbaarheid sowel as spoorvorming. Hoë vulstof/bindstof verhoudings is een van die kritiese faktore wat die kompakteerbaarheid van die betrokke mengsels beïnvloed, maar laer vulstof/bindstof verhoudings vir beter kompaksie het nie ’n beduidende toename in wielsporing teweeg gebring nie. Soos verwag het die tipe bindstof ’n beduidende invloed op kompakteerbaarheid sowel as spoorvorming. ’n Toename in bindstof bevorder verdigting, maar lei tot groter wielsporing. Polimeer modifisering verminder die wielsporing van ’n standard mengsel onder dieselfde beladingstoestand. Alhoewel modifisering wielsporing verminder, vereis dit hoër kompaksie temperature.Die toevoeging van die teenstropingsmiddel GripperL verminder spoorvorming, aggregaat stroping asook die tempo van spoorvorming van die Kwartsiet LAMBS mengsel as gevolg van die stropingsmeganisme. Lae digthede kan lei tot aansienlike vogskade en spoorvorming; veral as die aggregaat vatbaar is vir die invloed van vog. Daar blyk ’n temperatuur interval te wees waarin verdigting met die Superpave Gyratory Compactor bereik kan word; maar selfs ‘n klein temperatuurafwyking kan beduidende invloed op die resultate van spoorvorming hê. Temperatuurbeheer is baie belangrik indien sinvolle vergelykings tussen die sporingsgedrag van verskillende mengsels gemaak moet word. Lineêr elasties en eindige element analise is uitgevoer om te bepaal of verskillende toetskonfigurasies die spanningsverdeling binne die toetsmonsters en die spoorvorming affekteer. Dit is bevind dat die geometrie van toetsmonsters het ’n invloed op die spanningsverdeling in die monsters wat die sporingsresultate kan beïnvloed. Die briketmonsters in die laboratorium gee ook groter spoordiepte teenoor dieselfde mengsel wat in die veld getoets is. Daarom is dit belangrik om verteenwoordigende monsters te gebruik.

In 1987, Congress authorized a 5 year $150 million dollar research program called the Strategic Highway Research Program (SHRP). SHRP was divided into four major areas, including the asphalt research program. The asphalt research program was divided into six major research contracts, one such contract, SHRP-003A was called Performance Related Testing and Measuring of Asphalt Aggregate Interaction and Mixtures. Oregon State University performed the portion of this contract related to the development and validation of accelerated test procedures for aging, low temperature cracking, and moisture sensitivity of asphalt-aggreagte mixtures. This thesis contains five independent papers that discuss elements of the development, validation, and or implementation of these accelerated test procedures. In the first paper, the relationship between field performance and laboratory aging properties of asphalt-aggregate mixtures is discussed, including the relative importance of asphalt binder and aggregate type on the amount of aging experience. Based on this work recommended aging procedures are presented to simulate different environmental conditions and pavement age. The second paper makes use of the large body of resilient modulus data conducted as part of the SHRP research effort to compare data obtain in the diametral and the triaxial mode. It is not possible to give a relationship between triaxial and diametral resilient modulus, without describing specimen geometry and other test conditions. The third paper discusses the effect of aging on the thermal cracking properties of asphalt-aggregate mixtures. The temperature at which aging occurs affects the way cold temperature fracture properties change with time. Low temperatures result in quenching of the aging process, while high temperatures result in continued aging. The fourth paper discusses work conducted in association with the Oregon Department of Transportation to extend the environmental conditioning system (ECS) test procedure for moisture assessment to open graded mixtures. Comparison in the ECS of mixtures with and without anti-strip agents added indicates that they don't always decrease moisture damage potential. The final paper presents a discussion of asphalt chemistry and its relationship to asphalt-aggregate mixture performance. Using the SHRP asphalt model, aging and low temperature performance data collected at Oregon State University is explained. / Graduation date: 1995

M. Tech. Civil Engineering. / Aims to assess the influence of the type of binder on the evolution of the macro texture in asphalt at an early age. The objective are to : 1. To assess the approach and methodology of French asphalt design method. 2. To establish the contributors to the reduction of skid resistance of asphalt. 3. Identify effective methods and develop guidelines for improving the surface drainage of asphalt with the use of tests from the laboratory. Asphaltic materials and factors under investigation include: pervious asphalt, continuously grade asphalt and various asphalt surface characteristics and correlation with the Tri-dim laser.

The primary objective of this study is to investigate the suitability of utilizing dune sand as a paving construction material in hot desert-like areas of the world, where regions of sand dunes exist. The high availability, low cost, and excellent physical properties of the current surplus of elemental sulfur and the benefits given to asphaltic binders by sulfur raises the possibility of using sulfur in asphalt mixes to produce stable mixtures with locally obtainable dune sand. Characterization of various sulfur-asphalt-dune sand mixtures for highway construction were made. The materials used in this investigation were elemental sulfur, AR-4000 (60-70 pen.) asphalt, and dune sand from Yuma, Arizona. The main variables include (a)proportion of sulfur and asphalt in the binder, (b)amount of binder in the mixture, (c)curing temperature, (d)test temperature, and (e)mixing techniques. The various mixtures were prepared by the one-wet mixing cycle technique. Similar dune sand mixtures with asphalt only were evaluated for comparison purposes. The different mixes were evaluated by the Marshall method, tensile strength tests (double punch), compression tests (standard and immersion), flexural tests (standard), dynamic modulus tests (double punch), and microscopic examinations of sulfur-asphalt binders and sulfur-asphalt-dune sand mixtures (thin sections). Preliminary characterizations of the various mixes were made on the basis of their Marshall stability, flow, density, and air void contents. Other engineering properties such as tensile strength, compressive strength, modulus of rupture, dynamic modulus, and microscopic studies were determined for selected mixes. The results consistently indicated that the sulfur-asphalt-dune sand mixes exhibited superior engineering characteristics and performance as compared to similar mixes without sulfur. The overall conclusion drawn from this study is that the dune sand which is not normally accepted for use as aggregate in asphaltic mixtures, can be used with the utilization of sulfur-asphalt binder systems to produce paving mixtures with compatible or better engineering properties in comparison to conventional asphaltic concretes.

M. Tech. Civil Engineering. / Evaluates various laboratory test methods to assess rutting potential in the hot-mix asphalt (HMA) and the effects of compaction methods. To achieve this objective, rutting potential of HMA samples prepared and compacted in the laboratory, and in the field was evaluated using different laboratory test methods under a range of temperatures and loads.

La croissance de caution vis-à-vis l'utilisation des produits pétroliers dans la construction a nécessité le besoin de développement des alternatives. Le BTP, en particulaire pour le secteur routière, a un certain nombre des piste ou les produits pétrolières ont utilisés, par exemple le liant pour les enrobés comme les agents régénérant (pour recyclage des enrobés), mais aussi le produits qui sont utilisés sur le chantier comme les anti-adhérents (ARA) et les débituminants (BR). Alors, il y a une besoin de remplacer les produits d'origines pétrolières par les alternatives bio-sourcés. Ce présent ouvre est une partie d'un projet qui va développer une nouvelle filière dédiée à la production de nouvelles formulations pour le BTP à partir de la transformation des huiles végétales et des graisses animales. Ce thèse concerne les produits développés seront destinés au l'asphalte, et alors, deux types d'applications sont particulièrement visés : (i) des agents anti-adhérents et (ii) des agents régénérants. Un débituminant sera développé aussi. Les produits anti-adhérents ont pour fonction d'empêcher le bitume d'adhérer aux engins de travaux sans effet secondaire, théoriquement, sur la matrice liante.. L'objet du travail est de caractériser l'efficacité et l'innocuité des agents anti-adhérents développés dans le cadre du projet et de développer les méthodes expérimentales visant à les évaluer. Trois essais principaux ont été développés pour caractériser la performance et innocuité des anti-adhérents vis-à-vis des essais qui ont optimisé leur implémentation et paramètres. La performance des anti-adhérents a été caractérisé par l'essai de glissance des enrobés. L'innocuité des anti-adhérents ont été caractérisés par des essais de fendage sur les enrobés et par l'essai de la dégradation de bitume. L'essai de la dégradation de bitume a servi aussi comme une mesure de la performance de débituminant. Les essais sur les anti-adhérents commerciaux d'Etats-Unis et la France a trouvé que ils ont deux modes de fonctionnement : i) lixiviation du bitume et ii) en formation d'une interface entre le les enrobés et la surface métallique. Même comme les deux modes ont été trouvé dans des certains anti-adhérents, le mode interface ont été trouvé préférable, grâce à l'option de garder les mêmes applications du produit pour plusieurs cycles de usage. Ensuite, un produit - basé sur glycérol sourcé de l'agro-industrie - a été développé. Les débituminants commerciaux ont été essayé, aves les conclusions : i) les débituminants plus effectifs ont eu les plus grande % des esters et ii) que les esters chaines courtes (C7-10) d'hautes concentrations ont été trouvé les plus efficace. L'agent régénérant est destiné à régénérer le bitume vieilli issu des agrégats d'enrobés (RAP) en lui redonnant ses propriétés originelles et en assurant leur maintien dans le temps. Le travail sur les agents régénérants se compose de la caractérisation physico-chimique du vieillissement du bitume et du bitume vieilli avec l'agent. Plus précisément, le travail se serve des techniques de spectrométrie IRTF (avec imagerie) et thermogravimétrie. Dans ce contexte, une produit bio-sourcé a été évalué comme une régénérant. Pour la spectroscopie FTIR, une moyenne de polir le mastique a été développé pour rassuré la platitude des échantillons. La régénération du bitume a été observé avec la spectrométrie ITRF, donc quelques peaks (notamment les indices IC=O and IS=O) pendant 0-42 jours de vieillissement dans l'étuve (loin-durée). Il a été trouvé qu'une période de vieillissement de 14 jours à l'étuve était à peu près équivalente au bitume vieilli par un cycle de RTFOT + PAV en termes de rhéologie et de la pénétration. Le mastic (vieilli 14 jours) a ensuite été mélangé avec un agent de bio-source (à 7,5% en poids de mastic). Il a été constaté par imagerie FTIR que l'indicateur de l'oxydation IS=O a été réduit par l'incorporation de l'agent régénérant dans le bitume. / The growing health and environmental concerns brought on by the use of petroleum based products in the asphalt construction industry have necessitated the development of alternatives. Infrastructure, especially that involving transportation has many uses for petroleum products including, as fuel, as well as in asphalt pavement construction - where petroleum products have traditionally constituted the binder for the mix as well as the rejuvenating agents (for asphalt recycling) - along with various agents used in the construction process including bitumen removers and asphalt release agents. Thus, there is a need to replace petroleum base agents with bio-sourced and biodegradable substitutes. The present work is part of a project to develop bio-sourced (recycled from agricultural waste) products for the construction industry. This work is dedicated to developing products relating to the asphalt industry. Two types of product applications were envisioned: i) an asphalt release agent (ARA) and ii) an asphalt rejuvenating agent. Additionally, a bitumen remover (BR) developed as part of the work on the ARA. ARAs prevent asphalt from adhering to tools and equipment used in asphalt production, without producing overly negative side effects with regards to the pavement. Three principal tests methods were developed and optimized for the performance and damage to asphalt of the ARAs. The asphalt slide test was developed to quantify the performance of the ARA by sliding hot asphalt mix down a plate with the ARA applied. The testing of the damage to asphalt from ARAs consisted of testing an asphalt cylinder - in contact with an ARA for seven days - in indirect-tensile strength (ITS). The bitumen degradation test consisted of submerging a bitumen sample in an agent over a certain time and weighing the bitumen that did not dissolve in the agent. This was followed by the observation of the bitumen-ARA chemical interaction by FTIR spectrometry. This test served as an assessment of ARA damage to bitumen as well as of the performance of BRs. The testing of the commercial ARAs from both the French and USA markets found that they had two primary modes of functioning: i) by softening the bitumen and ii) by forming an interface between the asphalt and the metal surface. While some agents had elements of both, it was found that interface agents are preferable, due to the ability to use a single ARA application for multiple occasions. With this completed, a water-based bio-sourced substrate ARA - based on glycerol derived from agricultural waste - was developed. The commercially available BRs were tested as well, finding that i) the most effective BRs had the highest ester concentration and ii) that highly concentrated short chained ester (C7-10) were very effective bitumen dissolvers. The goal of rejuvenating agents is to regenerate the old bitumen from recycled asphalt pavement (RAP) by restoring the original properties and ensuring the stability of these properties over time. This part consisted of the development of methods for bitumen and aging, as well as characterization of the chemical rejuvenation of bitumen by FTIR spectrometry (including imaging) and thermogravimetric analysis. A bio-sourced rejuvenating agent was evaluated as well. For the imaging, a mastic polishing method was developed in order to attain as samples as flat as possible for the analysis. The bitumen rejuvenation was observed using FTIR spectroscopy analysis. Several peaks (notably IC=O and IS=O) were observed for bitumen oven aged up to 42 days (long term). It was found that an oven aging period of 14 days was roughly equivalent to bitumen aged by a RTFOT+PAV cycle it terms of rheology and penetration. The mastic (aged for 14 days) was then combined with a bio-sourced agent (at 7.5%w of mastic). It was found by FTIR imaging that the oxidation indicator IS=O, was reduced by the incorporation of the rejuvenating agent.