Mechanical assessment of the induction heating as a method to accelerate the drying process of cold porous asphalt mixtures

Cold mix asphalts present clear advantages such as the fact that they do not need to be heated, what results in lower energy consumptions and emissions, or the possibility to be transported long distances and manufactured on an offsite. However, their use is highly limited due to the long curing times that are needed to reach their final strength and the lower mechanical performance achieved comparing to hot mix asphalts. This paper studies induction heating as a process to accelerate the drying time of the emulsion and compares it, in terms of the mixture mechanical performance, with a more conventional method in which the cold sample is heated up in an oven. Different tests, as Cantabro, stiffness and Indirect tensile strength have been carried out. The mechanical results have shown that the induction heating could be a feasible alternative to increase the initial strength and reduce the opening time for this type of layers, although more research is necessary concerning the optimization of the mixture and the improvement of the induction device configuration.This paper was financed by the Spanish Ministry of Economy and Competitiveness with funds from the State General Budget (PGE) and the European Regional Development Fund (ERDF) through the research project SIMA+ (Ref. BIA2016‐77372‐R)

Long-Term Simulation of a System for Catchment, Pre-treatment and Treatment (SCPT) of Polluted Runoff Water

The effects of pollutants in runoff on the environment have forced the development of several water treatment systems with the aim of reducing this kind of pollution before its final discharge. Nevertheless, many of these systems do not behave satisfactorily and, additionally, there is a low level of confidence in the treatment performance. This paper introduces the results of research on the long-term performance of a laboratory prototype of a System for Catchment, Pre-treatment and Treatment (SCPT) designed to deal with the polluted runoff water. Solid and oil treatment efficiency were the focus of the study. After fourteen consecutive simulated rain events, the treatment efficiency levels achieved by the prototype are higher than 80% of solids and 90% of oils

Laboratory analysis of the infiltration capacity of interlocking concrete block pavements in car parks

Interlocking Concrete Block Pavements (ICBPs) have been widely used in car parks to reduce runoff. Researches have demonstrated that clogging is the most influential factor in the reduction of the infiltration capacity of this type of permeable pavement. Nevertheless, there is no laboratory study of the infiltration performance of ICBPs that combines clogging levels with variables related with the topography of car parks such as runoff surface length (RSL) and surface slope (SS). This paper studies the infiltration behaviour of ICBP during their operational life in a car park using an improved version of the Cantabrian Fixed (CF) Infiltrometer. This laboratory device simulates direct rainfall and runoff from adjacent impervious areas over an ICBPs surface of 0.25m2 for different slopes (0, 3, 5, 7 and 10%) and three scenarios of clogging (surface newly built, surface clogged and surface clogged with maintenance). This paper presents the results of the tests and a statistical analysis based on three regression models (corresponding to each clogging scenario) depending on the RSL and SS variables. All models passed a confidence level of 95%, presenting high R2 values and showing that RSL is a more influential variable than the SS for all clogging scenarios

Laboratory Analysis of the System for Catchment, Pre-treatment and Treatment (SCPT) of Runoff from Impervious Pavements

This article reports the development and construction of a 1:1 scale laboratory prototype of a System for Catchment, Pre-treatment and Treatment (SCPT) of runoff polluted by contaminants washed from impervious pavements. The concept of the SCPT is an online system with an up-flow filter. The filter is composed geotextile layers and limestone. Laboratory tests carried out were focused on determining the SCPT prototype behaviour under different working conditions. The variables studied were: inflow, pollutant loads and filtration system configuration. The results show that the designed system has a high capacity for total solids and oil treatment, with an average efficiency of 85% and 97% respectively. Moreover, the regression equations of the treatment efficiency have been determined for each of the studied pollutants, for different inflow conditions and pollution loads

Asphalt concrete mixture with recycled aggregates and modified bitumen at reduced temperature

The GREENROAD project was born to demonstrate a technically feasible alternative to conventional mixtures and to improve the sustainability of the road sector. The project involves the development of Asphalt Concrete mixture manufactured with steel slag of Electric Arc Furnace, which is produced in the region and currently implies a high environmental cost; RAP from other mixtures; and bitumen modified with end-of-life tyres. Besides, a wax has been used to decrease the manufacture temperature and improve the environmental impact. Finally, a mixture with more than 80% of recycled aggregates and with a decrease of temperature from 20°K to 30°K was achieved in laboratory, reaching the requirements for the maximum category of heavy traffic level (T00) of the Spanish specifications

Long-term analysis of clogging and oil bio-degradation in a System of Catchment, Pre-treatment and Treatment (SCPT)

Runoff contamination has motivated the development of different systems for its treatment in order to decrease the pollutant load that is discharged into natural water bodies. In the long term, these systems may undergo operational problems. This paper presents the results obtained in a laboratory study with a 1:1 scale prototype of a System of Catchment, Pre-treatment and Treatment (SCPT) of runoff waters. The analysis aims to establish the operational behaviour of the SCPT in the long term with respect to oil degradation and hydraulic conductivity in the geotextile filter. It is concluded that bio-degradation processes take place inside the SCPT and that hydraulic conductivity of the geotextile filtration system decreases slowly with successive simulated runoff events

Optimization of Compaction Quality Control in the Core of Random Fillings within Linear Infrastructures: Application to Metamorphic Slate Fillings

The construction of random fillings from the excavation of medium hardness rocks, with high particle sizes, presents limitations in compaction control. This research applies new control techniques with revised test procedures in the construction of the random fillings core, which constitutes the main part of the embankment, with the bigger volume and provides the geotechnical stability to the infrastructure. The maximum thickness over each of the compacted layers researched that made up the random fillings was 800 mm. As there are many types of rocks, this research is applied to metamorphic slates. Quality control was carried out by applying new research associated with the revision of wheel impression test, topographic settlements, and plate bearing test (PBT). Thus, new test procedures are established, defining efficient thresholds. Comparisons make it possible to choose representative tests, avoiding duplication. The optimization of control reduces inspection times, ensuring quality adapted to the high construction efficiency of diggings. Traditionally, rocks were rejected due to their maximum size, underutilizing the use of high-quality materials. Promoting their utilization implies a better use of resources, and therefore, a higher environmental efficiency. A statistical analysis of the core of 16 slate random fillings was carried out, with a total of 2250 in situ determination of density and moisture content, 75 wheel impression tests, 75 topographic settlement controls, and 75 PBT. The strong associations found between different tests allowed to simplify the quality control

Effect of Different Types of "Dry Way" Additions in Porous Asphalt Mixtures

ABSTRACT: Polymers are widely used to improve the mechanical performance of asphalt mixtures. Among them, styrene butadiene styrene (SBS) is the most commonly used, especially in the wet modification of virgin bitumen. This method, which is extensively utilized, has several advantages, but also some disadvantages, concerning its performance (such as the risk of instability or a lack of homogeneity) and logistical management (such as the need for special equipment, the transport of materials, and the dependence on the refinery that modifies the bitumen). This paper analyses the use of the most conventional types of polymers (two types of SBS, one type of BS, and rubber from end-of-life tires), dry added, as an alternative method. They have been used in porous asphalt mixtures. This type of bituminous mixture is usually designed with commercial polymer-modified bitumen, due to the mechanical requirements, and it is very sensitive to the properties of the binder used. The mechanical behavior of experimental porous asphalt mixtures has been significantly improved, especially in the case of SBS, although the performance did not reach that of commercial polymer-modified bitumen. The results have shown that the dry method is a suitable and feasible option to manufacture modified mixtures, especially considering its advantages, from a logistical viewpoint, in comparison with the wet method.The authors would like to recognize the funding from the Spanish Ministry of Science, Innovation and Universities (MCIU), the Spanish State Research Agency (AEI) and the European Regional Development Fund of the European Union (ERDF, EU) through the project HOFIDRAIN-MELODRAIN,Re. RTI2018-094217-B-C32, financed by MCIN/ AEI /10.13039/501100011033/ ERDF “A way to make Europe”

Laboratory Assessment of Water Permeability Loss of Geotextiles Due to Their Installation in Pervious Pavements

During the last decades, the importance of sustainable development in society has increased considerably. Sustainable Urban Drainage Systems (SUDS) are a group of techniques that aim to improve the management of rain and run-off water while reducing their pollution. Many of these systems incorporate geotextiles in their structures, which act as a layer separation and water filter. Some authors defend the idea that by simply being installed, geotextiles partially or totally lose their separation and filtering capacities. This study proposes a testing methodology that can reproduce this effect and obtain a reduction factor for the water permeability of the material after its installation, which is defined here as the ?new condition factor?. The procedure simulated the real installation conditions in the laboratory by causing the specimen to undergo both mechanical and hydraulic damage and subsequently measuring the loss of water permeability that it provoked on the geotextile. Two different nonwoven geotextiles were tested in order to validate the procedure and to obtain initial results that could confirm the need for the new condition factor in the design of pervious pavements with geotextiles. Analysis of variance (ANOVA) was used to determine the statistical significance of the test variableshis research was funded by the Spanish Ministry of Economy and Competitiveness, grant number BIA2012-32463, and by the Dirección de Investigación of the Universidad Católica de la Santísima Concepción, fund FAA 02/2018. The authors would like to thank the support and collaboration from the Construction Technology Research Group (Grupo de Investigación de Tecnología de la Construcción - GITECO), the Geosynthetics Laboratory of the University of Cantabria (LAGUC), Grupo de Caminos de Santander (GCS) and the Geotechnical Group of the University of Cantabria

Relationship between urban runoff pollutant and catchment characteristics

A lot of research has been done to determine levels of contamination in runoff from urban and rural catchment areas. Some authors compare their results with other authors, or look for relationships between the variations of pollutant concentration and the catchment characteristics but they seldom focus on determining the statistical significance of their results. This paper presents a review of 37 papers selected from a total of 169 papers consulted about runoff water quality throughout the world (America, Asia and Europe). The results presented in these 37 papers have been reviewed and statistically analyzed in order to evaluate the influence of catchment area characteristics (location, catchment area size, average daily traffic and type of land use) on the stormwater runoff pollution. It has been concluded that for the cases studied, most of the results about the polluting agents studied are comparable and no important element of the catchment characteristics had significant influence on the pollutants’ concentration