Nonlinear elastic behavior of bitumen emulsion-stabilized materials with C&D waste aggregates

[Abstract:] In this study, the nonlinear elastic behavior of bitumen-stabilized materials with emulsion (BSM-E)1 with recycled aggregates from construction and demolition (C&D)2 waste was analyzed using dynamic triaxial tests. Different prediction models were fitted to the experimental resilient modulus, the Mohr–Coulomb envelopes were obtained, and the Huurman’s model was fitted to the experimental creep data to provide the necessary parameters for eventual numerical simulations. The results show that mixtures with C&D aggregates are more flexible, have better resistance to permanent deformation, and similar failure stress compared with mixtures with natural aggregates. However, they needed a higher water and bitumen content

Aplicación sostenible de residuos de construcción y demolición como árido reciclado de mezclas bituminosas en frío

[Resumen] En la presente tesis se investiga el empleo de los Residuos de Construcción y Demolición (RCD) como áridos reciclados de mezclas bituminosas en frío. Esta nueva aplicación de los RCD en el ámbito de la construcción y mantenimiento de carreteras, contribuiría a reducir su deposición en vertederos, así como a limitar la explotación de canteras de árido natural. Los RCD mostraron ciertas propiedades particulares que los diferencian sensiblemente de los áridos naturales. Entre éstas, destaca su elevada absorción y su baja densidad y resistencia a fragmentación. Las mezclas bituminosas en frío, tipo grava-emulsión, con el 100% de árido reciclado y las de control, con el 100% de árido natural, fueron ensayadas para obtener sus propiedades volumétricas, afinidad árido-ligante y sensibilidad al agua, además de los parámetros propios de su comportamiento visco-elasto-plástico (resistencia a tracción indirecta, módulo resiliente a tracción indirecta, módulo dinámico, resistencia a la deformación permanente) y elástico no lineal (por medio de ensayos triaxiales como el de módulo resiliente y resistencia a la deformación permanente). Los resultados muestran que los RCD no solo son aptos para el uso general en carreteras de medio/bajo tráfico sino que incluso mejoran algunas propiedades de las mezclas en comparación con las fabricadas con áridos naturales.[Resumo] Na presente tese investígase o emprego dos Residuos de Construción y Demolición (RCD) como áridos reciclados de mesturas bituminosas en frío. Esta nova aplicación dos RCD no ámbito da construción e mantemento de estradas, contribuiría a reducir a súa deposición en vertedoiros, así como a limitar a explotación de canteiras de árido natural. Os RCD mostraron certas propiedades particulares que os diferencian sensiblemente dos áridos naturais. Entre estas, destaca a súa elevada absorción e a súa baixa densidade e resistencia á fragmentación. As mesturas bituminosas en frío, tipo grava-emulsión, co 100% de árido reciclado e as de control, co 100% de árido natural, foron ensaiadas para obter as súas propiedades volumétricas, afinidade árido-ligante e sensibilidade á auga, ademais dos parámetros propios do seu comportamento visco-elasto-plástico (resistencia á tracción indirecta, módulo resiliente a tracción indirecta, módulo dinámico, resistencia á deformación permanente) e elástico non lineal (por medio de ensaios triaxiais coma o de módulo resiliente e resistencia á deformación permanente). Os resultados mostran que os RCD non só son aptos para o uso xeral en estradas de medio/baixo tráfico senón que incluso melloran algunhas propiedades das mesturas en comparación coas fabricadas con áridos naturais.[Abstract] In this thesis, the use of Construction and Demolition Waste (CDW) as aggregates in cold asphalt mixtures is studied. This new application of the CDW in the scope of the construction and maintenance of roads, would help to reduce their disposal in landfills, as well as limit the working of natural quarries. The CDW aggregates shown specific properties which make them different from other sorts of natural aggregates. Among them, it is particularly noteworthy the high absorption and the low density and resistance to fragmentation. Cold asphalt mixtures, grave-emulsion type, with 100% of recycled aggregates and control mixes, with 100% of natural aggregates, were tested in order to obtain their volumetric properties, aggregate-binder affinity and resistance to water damage, as well as the parameters of their visco-elasto-plastic behavior (indirect tensile strength, indirect tensile stiffness modulus, dynamic modulus and resistance to permanent deformation) and non-linear elastic behavior (by means of triaxial tests, such as resilient modulus and resistance to permanent deformation). The results show that CDW are not only suitable for general use in medium/low traffic roads, but also they improve some properties of cold asphalt mixes when compared with those made just with natural aggregates

Mezclas bituminosas en frío con RCD

[Resumen:] En la presente investigación se estudió el empleo de los Residuos de Construcción y Demolición (RCD) como áridos reciclados de mezclas bituminosas en frío. Mezclas bituminosas en frío, tipo grava-emulsión, con el 100% de árido reciclado y de control, con el 100% de árido natural, fueron ensayadas para obtener sus propiedades volumétricas, además de los parámetros propios de su comportamiento visco-elasto-plástico (resistencia a tracción indirecta, módulo resiliente a tracción indirecta, módulo dinámico, resistencia a la deformación permanente) y elástico no lineal (por medio de ensayos triaxiales como el de módulo resiliente y resistencia a la deformación permanente). Los resultados muestran que los RCD no solo son aptos para el uso general en carreteras de medio/bajo tráfico sino que incluso mejoran algunas propiedades de las mezclas en comparación con las fabricadas con áridos naturales.[Abstract:] In this investigation, the use of Construction and Demolition Waste (CDW) as aggregates in cold asphalt mixtures was studied. Cold asphalt mixtures, grave-emulsion type, with 100% of recycled aggregates and control mixes, with 100% of natural aggregates, were tested in order to obtain their volumetric properties, as well as the parameters of their visco-elasto-plastic behavior (indirect tensile strength, indirect tensile stiffness modulus, dynamic modulus and resistance to permanent deformation) and non-linear elastic behavior (by means of triaxial tests, such as resilient modulus and resistance to permanent deformation). The results show that CDW are not only suitable for general use in medium/low traffic roads, but also they improve some properties of cold asphalt mixes, compared with those made just with natural aggregates

A proposed methodology for the global study of the mechanical properties of cold asphalt mixtures

[Abstract:] Despite having been used for decades, the structural performance of emulsion-treated materials has still not been investigated as intensely as in the case of hot-mix asphalt (HMA). Proof of this is the lack of evolution of specific technical tests and standards. Due to this, many studies with cold asphalt mixtures (CAM) are carried out based on HMA specifications. Throughout the present paper, a new methodology is proposed in order to study different mechanical properties of CAM, such as unconfined compression strength (UCS), indirect tensile strength (ITS) and indirect tensile stiffness modulus (ITSM) not only in an independent way but also by giving a global approach. The consistency and applicability of the method is discussed and from its application to a practical case study with two very different CAM, new conclusions about their performance are laid down

Recycled aggregates (RAs) for asphalt materials

[Abstract:] In this chapter, we gather the results of the most innovative studies about recycled aggregates (RA) from construction and demolition waste (CDW), in an attempt to better understand the physical and mechanical performance of these materials, which are more economical, sustainable and environmentally friendlier, as an integral part of bituminous mixtures.Ministerio de Educación y Ciencia; BIA2010–1775

Binder–aggregate adhesion and resistance to permanent deformation of bitumen-emulsion-stabilized materials made with construction and demolition waste aggregates

[Abstract:] Bitumen-stabilized materials with emulsion (BSM-E) are gaining increasing importance within the scope of road pavement engineering and the fight against climate change. Both environmental and economic aspects of BSM-E can be further improved by substituting the natural aggregates (NA) with recycled construction and demolition waste aggregates (CDWA). The objective of the present paper is to analyze how such substitution affects the two critical properties that mostly define the durability and long-term performance of BSM-E: resistance to stripping and resistance to permanent deformation. The stripping phenomena were analyzed in terms of binder–aggregate affinity through the Rolling Bottle Test and Boiling Water Test. The results showed that the weak mortar that attached to the aggregate surface produced poorer binder–aggregate affinity when the samples were subjected to mechanical agitation. However, the recycled aggregates did not affect the affinity at high temperatures and improved the resistance to permanent deformation, leading to failure of the material after many loading cycles

Effects of the use of construction and demolition waste aggregates in cold asphalt mixtures

[Abstract:] Cold asphalt mixtures (CAM) with 100% recycled aggregates from construction and demolition waste (CDW) were researched to ecologically and economically improve cold asphalt mixtures. The present study indicates that the UCS, ITS, ITSM and moisture susceptibility were very satisfactory not only compared with a control mix with 100% natural aggregates (NA) but also with values given by different standards and recommendations. A new global approach to design these aggregates has also been explored because conventional methods are inaccurate in this case

Performance of high rap half-warm mix asphalt

[Abstract:] The current global situation regarding climate change makes it necessary to promote the circular economy and the use of more environmentally friendly technologies in the construction sector. To that end, it is of interest to deepen our understanding of the performance of half-warm mix asphalt (HWMA) manufactured with high proportions of reclaimed asphalt pavement (RAP). Thus, in the present study, a laboratory analysis was carried out in which the behavior of HWMA manufactured with 100% RAP and without rejuvenators was compared with that of a control mix, i.e., an HWMA manufactured with 0% RAP. In particular, we analyzed the compaction energy with a gyratory compactor, mixing time and temperature, volumetric properties, moisture damage resistance through indirect tensile tests after immersion (ITS), stiffness based on the resilient modulus, resistance to permanent deformation using wheel tracking tests, and fatigue resistance through indirect tensile fatigue tests (ITFT). Both mixtures displayed adequate volumetric and mechanical properties, but the performance of the high-RAP HWMA was better than that of the control mixture in terms of resistance to permanent deformation in hot areas. In addition, the high-RAP HWMA without rejuvenators could provide energy and material savings, thus promoting sustainable development

Characterization of hot-mix asphalt made with recycled concrete aggregates that have been cured for 4 hours in the oven

[Abstract:] In this research a laboratory characterization of hot-mix asphalt (HMA) made with recycled concrete aggregates (RCA) from construction and demolition waste (CDW) as base layer in road construction has been conducted. HMA containing 5%, 10%, 20% and 30% of RCA in place of virgin aggregate were evaluated. To improve water resistance of the mixtures, they were left in an oven for 4 hours at mixing temperature before compaction to allow the bitumen absorption and, in addition, obstructing the mortar pores, strengthening the attached mortar onto the RCA surface and thus, preventing water pathways. The tested mixtures complied with Spanish water resistance requirement and also showed a water resistance performance much higher than that of the mixtures that were not cured in the oven. Stiffness and resistance to permanent deformation were also studied showing satisfactory results

Recycled construction and demolition waste in Cold Asphalt Mixtures : evolutionary properties

[Abstract:] The use of Cold Asphalt Mixtures (CAM) usually results in financial and environmental saving, while decreasing pollution and occupational hazards. However, they require a length of curing time to reach their full potential. Regarding ecological and financial implications, CAM can be further improved when produced with 100% recycled materials from Construction and Demolition Waste (CDW). In this paper, the evolutionary properties of CAM with CDW were studied in terms of stiffness growth and water loss and the results were compared with conventional control mixes. Among other conclusions, the results showed that although CAM with CDW lost water during longer curing periods, higher stiffness can be obtained with CDW than with Natural Aggregates (NA) at any curing time