Browsing by Author "Thenoux, Guillermo"
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- ItemControlling asphalt aging by inclusion of byproducts from red wine industry(ELSEVIER SCI LTD, 2012) Calabi Floody, Alejandra; Thenoux, GuillermoWorldwide around 95% of pavements contain Asphalt Binder (AB). Mainly, due to oxidation process, asphalt hardens and increases the pavement susceptibility to cracking. On the other hand, wine industry generates almost ten million tons of grape pomace residues per year. This byproduct is rich in antioxidants (ORAC 650 mu mol TE/g). The aim of the present work was to determine the antioxidant potential of grape pomace from Cabernet Sauvignon in AB to control the asphalt age hardening. To evaluate the performance of the antioxidant, samples were aged according to SUPERPAVE standards (RTFOT and PAV) and physical, chemical, and rheological properties were analyzed. For samples with 10% pomace, the increase in viscosity at 60 degrees C and fatigue factor after PAV aging decreased by 19% and 14% respectively. An increase of 23% of m-value was also observed. These results strongly suggest that grape pomace is a suitable alternative as antioxidant for AB to reduce age hardening. (C) 2011 Elsevier Ltd. All rights reserved.
- ItemDevelopment of a methodology for measurement of vehicle dust generation on unpaved roads(NATL ACAD SCIENCES, 2007) Thenoux, Guillermo; Bellolio, Juan Pablo; Halles, FelipeThis paper presents the results of a field study aimed at developing a methodology for measuring vehicle dust generation on an unpaved road. The methodology is based on the use of portable standard equipment known as Dust Mate. This equipment measures the number of particles per cubic centimeter for different particle sizes: particles less than 10, 2.5, and 1 mu m in diameter. The methodology was developed. to improve the management of unpaved roads and to study the performance of earth road dust suppressants. The Dust Mate equipment may be mounted in various types of vehicles, and measurements may be performed at various speeds. The equipment can record dust generation continuously and may be programmed to save the data for measurements over various time spans. This last feature will allow evaluation of short segments of the road (less than 10 m). The study was performed in three stages: determination of (a) the best design position of the equipment for different types of vehicles in combination with the effect of speed, (b) the repeatability of results for different operation parameters, and (c) the effectiveness of various dust suppressants. The research was done on test sections of unpaved mining and rural roads with different types of soil and surface conditions. The study indicates that the methodology developed for dust measurement with the Dust Mate equipment may be considered an improvement over the methods currently in use. The measurements are reliable, and the repeatability of the results is better than is required by today's standards.
- ItemEnergy consumption comparison for different asphalt pavements rehabilitation techniques used in Chile(ELSEVIER SCIENCE BV, 2007) Thenoux, Guillermo; Gonzalez, Alvaro; Dowling, RafaelIn developing countries without the availability of reliable pavement management systems, recycling techniques may offer the best alternative for pavement structural rehabilitation. However, for many government officials and contractors there is a clear understanding of the technical advantages of recycling but not a clear perspective of cost saving. Since cost is a relative value among different regions of any country the following work makes an energy analysis of the construction process of the three different rehabilitation techniques available in Chile. Three different structural pavement rehabilitation alternatives were studied and compared using an energy consumption methodology:
- ItemInterpretation of laboratory and full-scale testing of New Zealand foamed bitumen pavements using finite-element modelling(TAYLOR & FRANCIS LTD, 2012) Gonzalez, Alvaro; Cubrinovski, Misko; Alabaster, David; Thenoux, GuillermoA large research project on foamed bitumen (FB) stabilisation was conducted in New Zealand. The project consisted of an extensive laboratory and full-scale testing of FB pavements. The objective of this paper is to interpret the performance of FB pavements by using finite-element (FE) modelling. The mechanical properties of the materials were calculated using testing data and used as material inputs in the FE modelling. The MohrCoulomb and DruckerPrager material models were adopted to calculate plastic deformation, which is related to pavement rutting. Results of the modelling indicate that increasing the FB content increases the tensile strength and modulus of the pavements, reducing the plastic deformations in the subgrade and the stabilised layer. In addition, adding FB reduces sensitivity to rutting when pavement is overloaded or the asphalt surface layer is cracked.
- ItemLaboratory and field evaluation of fluid bed combustion fly ash as granular road stabilizer(NATL ACAD SCIENCES, 2007) Thenoux, Guillermo; Halles, Felipe; Vargas, Angeles; Bellolio, Juan Pablo; Carrillo, HectorThis paper presents the result of laboratory and field research on soil stabilization using fluid bed combustion fly ash. This type of ash is the result of the combustion of petroleum coke and limestone in an electric power generation plant (Petropower, located in the south of Chile), which makes it different from other types of ash used regularly in soil stabilization. The ash differs from the traditional ash used in soil stabilization, particularly because of (a) a high concentration of lime that may produce cementing compounds and (b) the presence of sulfates that may produce a secondary reaction such as the formation of gypsum and ettringite, resulting in a different level of expansion in some types of soils. The main objectives of the research were to characterize fluid bed combustion fly ash from the Petropower plant and to evaluate the technical feasibility of using this ash as a soil stabilizer. The laboratory and field research showed that this type of ash improves the mechanical properties and water susceptibility of most types of soils. Although laboratory experimentation proves that the secondary reaction produces soil expansion in clayey soils, field experimentation indicates that the secondary reaction that produces soil expansion may be controlled by an adequate laboratory design and an appropriate dose of fly ash.
- ItemThree-dimensional finite element model for flexible pavement analyses based on field modulus measurements(KING FAHD UNIV PETROLEUM MINERALS, 2008) Lacey, Geraint; Thenoux, Guillermo; Rodriguez Roa, FernandoIn accordance with the present development of empirical-mechanistic tools, this paper presents an alternative to traditional analysis methods for flexible pavements using a three-dimensional finite element formulation based on a linear-elastic perfectly-plastic Drucker-Prager model for granular soil layers and a linear-elastic stress-strain law for the asphalt layer. From the sensitivity analysis performed, it was found that variations of +/- 4 degrees in the internal friction angle of granular soil layers did not significantly affect the analyzed pavement response. On the other hand, a null dilation angle is conservatively proposed for design purposes. The use of a Light Falling Weight Deflectometer is also proposed as an effective and practical tool for on-site elastic modulus detennination of granular soil layers. However, the stiffness value obtained from the tested layer should be corrected when the measured peak deflection and the peak force do not occur at the same time. In addition, some practical observations are given to achieve successful field measurements. The importance of using a 3D FE analysis to predict the maximum tensile strain at the bottom of the asphalt layer (related to pavement fatigue) and the maximum vertical compressive strain transmitted to the top of the granular soil layers (related to rutting) is also shown.