Thesis (PhD)--Stellenbosch University, 2014. / ENGLISH ABSTRACT: The increased use of reclaimed asphalt (RA) in Bitumen Stabilised Materials (BSMs), shortcomings in the existing design guidelines and manuals and ongoing developments in the concepts and understanding of these materials require further research into the fundamental properties and behaviour of BSMs. The state-of-the-art of foamed bitumen techniques is reviewed in the literature study. Current best practices in the design of BSMs and pavements incorporating such materials are also included in this literature study. Shortcomings and areas for further improvement of the design practice have been identified. With new environmental legislation, the importance of BSM technology including RA as an environmentally-friendlier and more sustainable construction technique is set to increase in the coming years. Changes in the behaviour of materials and failure mechanisms of BSM mixes are long-term phenomena. This implies that the study of the physico-chemical and mechanical properties of the mixes with increasing amount of RA is vital. Therefore, fundamental understandings of moisture damage and thermo-physical characteristics, which are related to material properties, are required. The main objective of this study is to advance BSM technology by assessing the influence of the selected materials on durability behaviour, temperature distribution and long-term performance in all phases of application (i.e. mix design, construction, and in-service condition). This study begins with a comprehensive literature review of research dealing with the interactions between RA and mineral aggregates. The properties of RA and mineral aggregates were reviewed. This was followed by a review into the mechanical properties of BSM-foam mixes with high percentage of RA and its durability performance. Factors influencing the temperature gradient of BSMs were then identified. Achieving a better understanding of the fundamental performance properties and temperature influence on the behaviour of BSMs with high percentage of RA is one of the key factors of this research, with a view to using the extended knowledge for improvements to current mix design and structural design practices. Finally, the fundamental theories on thermo-conductivity and the mechanical properties of the BSM were used to create a relationship between temperature and mechanical properties in a pavement section. A laboratory testing programme was set up to study the properties and behaviour of BSMs and to establish links with the compositional factors, i.e. the type of binder used, the percentage of RA in the mix and the addition of a small amount of cement as active filler. BSMs were blended in three different proportions of RA and good quality crushed stone materials: 100% RA (with 2 % bitumen content), 50% RA and 50% G2 Hornfels crushed stone (with 2.1% bitumen content) and 100% G2 (with 2.3 % bitumen content). Tri-axial testing was carried out to determine shear parameters, resilient modulus and permanent deformation behaviour, while brushing testing was carried out to determine the possible durability performance of the BSMs. The mixture durability in terms of moisture damage was investigated. Temperature data were collected and a model to accurately simulate the temperature distribution in the BSMs was identified and proposed for further investigation and validation. It was found from the laboratory temperature data collected in this study that the temperature gradient varied according to the depth of the BSMs. A considerable part of the efforts of this study were dedicated to characterise and model the temperature distribution in a pavement section, taking into account the mechanical properties and performance of the BSMs at different temperature layers. The study provides an insight into fundamental mechanical performance, material durability properties, and the thermal capacity and conductivity of the BSM-foam mixes with high percentage of RA. This will assist in improving the current procedure for selection, combining and formulation of the mix matrices for BSMs. In addition, the study provides guidelines that will enable practitioners to confidently understand the relationship between temperature gradient and mechanical behaviours of BSM-foam pavement section. The specific durability-related issues addressed in this study are substance for future research. / AFRIKAANSE OPSOMMING: Die toenemende gebruik van herwonne asfalt (Engels: reclaimed asphalt (RA)) in bitumen gestabiliseerde materiaal (Engels: Bitumen Stabilised Materials (BSMs)), tekortkominge in die bestaande ontwerpriglyne- en handleidings en deurlopende verbeteringe in die konsepte en begrip van hierdie material vereis verdere navorsing oor die fundamentele eienskappe en gedrag van BSM. In die literatuurstudie word die huidige stand van kennis van die ontwerp van skuimbitumentegnieke ondersoek. Die literatuurstudie dek ook die huidige beste praktyke in die ontwerp van BSM en plaveisels wat hierdie materiale insluit. Tekortkominge en areas van verdere verbetering in die ontwerppraktyke is geïdentifiseer. Onlangse omgewingswetgewing verhoog die belangrikheid van BSM tegnologie, insluitend RA, as ‘n meer omgewingsvriendelike en volhoubare konstruksie-tegniek. Hierdie faktor sal in die toekoms al hoe belangriker word. Die verandering in die gedrag van materiaal en die falingsmeganismes van BSM mengsels is langtermynverskynsels. Dit impliseer dat die studie van die fisio-chemiese en meganiese eienskappe van mengsels met toenemende verhoudings van RA van kardinale belang is’n Fundamentele begrip van die vogskade en temo-fisiese eienskappe, wat verwant is aan die materiale se eienskappe, word vereis. Die primêre doelwit van die studie is die bevordering van BSM tegnologie deur die invloed van die geselekteerde materiale op duursaamheid, temperatuurverspreiding en langtermyn gedrag in al die fases van toepassing (mengselontwerp, konstruksie en in-dienstoestand) te bepaal. Die verhandeling begin met ‘n omvattende literatuuroorsig van navorsing oor die interaksie tussen RA en mineraalaggregate. Die eienskappe van RA en die mineraalaggregate word bespreek. Dit word gevolg deur ‘n oorsig van die meganiese eienskappe van die BSM-skuimbitumenmengsels met ‘n hoë persentasie RA en die duursaamheidgedrag daarvan. Faktore wat die temperatuurgradient van BSM beïnvloed word dan aangetoon. ‘n Beter begrip van die fundamentele gedragseienskappe en die invloed van temperatuur op die gedrag van BSM met ‘n hoë persentasie RA is een van die sleutelfaktore van hierdie navorsing. Dit het ten doel om die uitgebreide kennis te gebruik om huidige mengselontwerp en strukturele ontwerppraktyke te verbeter. Laastens is die fundamentele teorie van termogeleiding en die meganiese eienskappe van BSM gebruik om ‘n verhouding tussen temperature en meganiese eienskappe in ‘n plaveiselsnit te ontwikkel. ‘n Laboratoriumtoetsprogram is opgestel om die eienskappe en gedrag van BSM te bestudeer en om verwantskappe tussen samestellende faktore soos die tipe bindmiddel gebruik, die persentasie RA in die mengsel en die toediening van klein hoeveelhede sement as aktiewe vuller te bepaal. BSM is in drie verskillende verhoudings van RA en goeie gehalte gebreekte klipmateriaal vermeng: 100% RA met 2 % bitumen, 50% RA en 50 % G2 Hornfels gebreekte klip met 2.1 % bitumen en 100% G2 met 2.3 % bitumen. Drie-assige druktoetse is gebruik om skuifsterkteparameters, elastiese modulus en permanente vervormingsgedrag te bepaal. Borseltoetse is gebruik om die duursaamheidgedrag van BSM te bepaal. Die mengsels se duursaamheid is ook in terme van vogskade ondersoek.

Diante da retomada do crescimento do agronegÃcio do AgropÃlo do Baixo Jaguaribe, a melhoria da malha viÃria da regiÃo tornou-se imprescindÃvel. No entanto, o baixo volume de trÃfego registrado nas rodovias locais, a baixa qualidade dos materiais ocorrentes na regiÃo e os parcos recursos disponÃveis para investimentos em infra-estrutura, inviabilizam economicamente os empreendimentos rodoviÃrios. Tornou-se entÃo necessÃria a busca por soluÃÃes alternativas que reduzam os custos de implementaÃÃo e melhoria de pavimentos. Acredita-se que a adiÃÃo de emulsÃo asfÃltica aos solos ocorrentes na regiÃo, devido Ãs suas propriedades aglutinantes e impermeabilizantes, pode constituir-se em uma dessas alternativas. O objetivo deste trabalho foi avaliar a viabilidade tÃcnica da estabilizaÃÃo betuminosa de solos ocorrentes no AgropÃlo do Baixo Jaguaribe, no Estado do CearÃ, para o emprego em camadas de base de rodovias. Para tanto, foram selecionados trÃs solos da regiÃo para o estudo da estabilizaÃÃo com a adiÃÃo da emulsÃo asfÃltica de ruptura lenta (RL-1C). As variÃveis investigadas foram o teor de emulsÃo aplicado (2%, 5% e 8%), o tempo de cura seca ao ar livre (sem cura, 7 dias e 28 dias de cura), e a forma de distribuiÃÃo da emulsÃo (distribuiÃÃo uniforme ou em gradiente decrescente com a profundidade). As misturas solo-emulsÃo foram submetidas à avaliaÃÃo da resistÃncia mecÃnica (por meio dos ensaios de resistÃncia à compressÃo simples, resistÃncia à traÃÃo por compressÃo diametral, Ãndice de Suporte CalifÃrnia e mÃdulo de resiliÃncia) e à avaliaÃÃo da resistÃncia ao desgaste e à abrasÃo (por meio dos ensaios adaptados Loaded Wheel Test â LWT e Wet Track Abrasion Test â WTAT). Foi observado que a estabilizaÃÃo betuminosa promoveu incrementos de resistÃncia das amostras de solos estudadas, sendo essa resistÃncia dependente da umidade residual dos corpos de prova no momento da realizaÃÃo do ensaio. Os resultados indicaram tambÃm que a adiÃÃo de emulsÃo asfÃltica tem efeitos distintos para os vÃrios tipos de solos, sendo que a quantidade de sÃlica presente nas amostras parece influenciar a qualidade das misturas solo-emulsÃo. Conclui-se, à luz dos ensaios realizados, que algumas amostras de solos ocorrentes na RegiÃo do Baixo Jaguaribe podem ser satisfatoriamente estabilizadas com emulsÃo asfÃltica. / Taking into account that the agribusiness of Baixo Jaguaribeâs Agricultural Pole is developing again, it is essential to improve the road network of the area. However, the low traffic volume observed in the local highways, the low quality of the materials in the area and the limited available resources to invest on infrastructure make the road constructions economically unfeasible. Therefore, it became necessary to search for alternative solutions that reduce the implementation costs and improve pavements. It is considered that the addition of asphalt emulsion to the soils in the area can be one of those alternatives, due to its agglutinative and waterproof properties. The objective of this work was to evaluate the technical viability of the bituminous stabilization of soils occurring in the Agricultural Pole of Baixo Jaguaribe, in the State of CearÃ, to be used in base layers of highways. For that purpose, it was selected three soils on the area to the study of the stabilization with the addition of a cationic slow setting asphalt emulsion. The variables investigated were the rate of emulsion applied (2%, 5% and 8%), the open air dry curing time (without cure, 7 days and 28 days), and the emulsion distribution (uniform distribution or in decreasing gradient with depth). The soil-emulsion mixtures were evaluated regarding their mechanical resistance (through the compression strength test, diametrical compression test, California Bearing Ratio and the resilience modulus test) and their resistance to wearing and abrasion (through the adapted tests Loaded Wheel Test - LWT and Wet Track Abrasion Test - WTAT). It was observed that the bituminous stabilization produced an increase in the resistance of the soil samples studied, that resistance being dependent on the residual humidity of the test specimens in the moment of test conduction. The results also indicated that the addition of asphalt emulsion has different effects for the several types of soils, so that the amount of silica present in the samples seems to influence the quality of the soil-emulsion mixtures. According to the tests carried out, it was concluded that some samples of soils present in the area of Baixo Jaguaribe can be satisfactorily stabilized with asphalt emulsion.

Currently it is important to address the re-use of building materials from construction reconstructed or upgraded roads. Commonly used technologies cold and hot asphalt recycling are starting using to complement with technologies using cold asphalt mixtures with rejuvinators or softeners. This type of asphalt mixtures could be used in pavement constructions with lower traffic load. This thesis deals with the design and laboratory assessment of unbound and bound mixtures R-material and recycled concrete. This thesis is experimentally testing the possibility of using functional tests to optimize the design of asphalt mixture with 100% representation of R-material with a possible revival of asphalt emulsion with a rejuvenator.

The thesis is focused on the use of R-material into cold asphalt mixtures. It deals with cold recycling and with input materials for this technology. It verifies properties of R-material and residues of bituminous binder. It also verifies properties of designed cold asphalt mixtures by the probative controls (indirect tensile strenght and water resistance). Furthermore is focused on the experimental measurement of selected mixtures to ensure more characteristics. The amount of homogenity of R-material, quantity and quality of residues bituminous binder is essential for positive results.

En el desarrollo del presente trabajo, se plantea desde el punto de vista técnico económico la importancia de la interacción de las partículas finas presentes en el mastic para dos técnicas que se presentan como innovadoras en el mundo de reciclado (RAP) de carreteras, tratamiento de carpetas con asfalto espumado y tratamiento con emulsiones asfálticas. Esta investigación se llevó a cabo en el proyecto “Servicio de reciclado Huancayo – Yanango – puente Herrería tramo III. Conforme se avanza en la investigación, se analiza y sintetiza una extensa revisión de bibliografía sobre la aplicación de las técnicas de tratamiento de carpetas con asfalto espumado y emulsiones asfálticas, de cada una se explica su historia, uso, producción, diseño para su desarrollo. Posteriormente, se explica la metodología para tener la secuencia del proceso para ambas técnicas, identificar la población, el tamaño de la muestra y las variables. Se da pase a la descripción del proyecto, en donde se presenta su ubicación, las características esenciales, el estudio de tráfico y estudio de la condición antes del proyecto. Además, se estudia las muestras y el resultado de los ensayos de pavimentos donde se ven las calicatas, el triturado de RAP a dimensiones de suelo, cálculo del número estructural de acuerdo con la resistencia saturada, resultados técnicos con asfalto espumado, con emulsión asfáltica, discusión de la solución adoptada y comparación económica de ambas técnicas. Finalmente, las conclusiones y recomendaciones que se encontraron en la presente investigación. / In the development of this work, the importance of the interaction of the fine particles present in the mast for two techniques that are presented as innovative in the world of road recycling (RAP), treatment of folders with foamed asphalt and treatment with asphalt emulsions. This research was carried out in the project "Recycling service Huancayo - Yanango - Herrería bridge section III. As the research progresses, an extensive review of the literature on the application of folder treatment techniques with foamed asphalt and asphalt emulsions is analyzed and synthesized, each of which explains its history, use, production, and design for its development. Subsequently, the methodology is explained to have the process sequence for the techniques, to identify the population, the sample size, and the variables. The description of the project is given, where its location, the essential characteristics, the traffic study and the condition study before the project are presented. In addition, the samples and the results of the tests of pavements where the test pits are seen, the grinding of RAP to soil dimensions, calculation of the structural number according to saturated resistance, technical results with foamed asphalt, with asphalt emulsion, are studied. discussion of the adopted solution and economic comparison of both techniques. Finally, the conclusions and recommendations found in the present investigation. / Tesis

The first objective of this research was to investigate temporal trends in the mechanical properties of base materials stabilized with asphalt emulsion and to assess the rate at which emulsion-treated base (ETB) design properties are achieved. The second objective of this research was to identify construction and environmental factors most correlated to specific mechanical properties of ETB layers and to determine which construction factors exhibit the greatest variability. Additional statistical analysis was performed to determine if significant differences existed between different test sections on a given project. In this research, three experimental sections were established along a pavement reconstruction project near Saratoga Springs, Utah. Field tests were performed to assess the structural properties of the ETB immediately following construction and at 2, 3, 7, and 14 days; 4 months; and 1 year. Measured values were plotted against time to determine trends in ETB strength development. Several statistical analyses were then performed on the collected data. Modulus values were consistently low in all three sections during the first two weeks of testing, increased dramatically by 4 months, and then decreased considerably by 1 year. During the first two weeks following construction, the average ETB structural coefficient was 0.04. Only two of the three sections reached the design structural coefficient of 0.25, which occurred after approximately 3 months; however, the average structural coefficient measured for all three sections after 1 year of curing, which included a winter, was only 47 percent of the design strength. The results of this research show that, while pavement capacity is sufficient at 4 months, it is severely reduced during the first two weeks and at 1 year. Trafficking under these reduced capacities is not recommended. Statistical analysis showed that gradation, binder change during emulsion treatment, and moisture content have the most significant impact on ETB structural properties. Gradation and binder change during emulsion treatment also exhibited significant variability; tighter specifications on material gradations and improved uniformity in emulsion distribution should therefore be considered. Because of the negative impacts of moisture on ETB strength development, construction should not be performed in conditions of excess moisture.