Recycled bio-sourced glycerol and diglycerol for asphalt release agents (ARA)

The objective of this study is to develop bio-sourced waste chemicals for use as asphalt release agents. Glycerol was extracted from bio-sourced waste and transformed by transesterification into the surfactants undecenoates of glycerol (MUG) and undecenoates of diglycerol (MUDG). They were composed of glycerol, monoglycerol, diglycerol, triglycerol, tetraglycerol and water. The formulations were mixed separately with water at quantities of 5–50%, along with acetone and commercial bio-sourced ARAs in order to observe the effects. The formulations were subjected to performance testing with the asphalt slide test, finding significant reduction in adhesion for a number of different formulations. The interaction of the formulations with bitumen was tested by the bitumen degradation test, which was combined with FTIR–ATR analysis, finding that the formulations do not dissolve the bitumen, but rather were adsorbed by the bitumen. The effects on asphalt mix of the best performing formulation, MUG at 20% in water, was tested by indirect tensile strength, determining that the formulation was acceptable for use in the field

Identification et caracterisation de la microfissuration dans les betons hydrauliques

SIGLECNRS T Bordereau / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc

Methods for Analyzing the Chemical Mechanisms of Bitumen Aging and Rejuvenation with FTIR Spectrometry

WOS:000381366300017International audienceThe recycling of asphalt is a process where old pavement is broken up and used as reclaimed asphalt pavement (RAP) in new asphalt pavement, often with the aid of recycling agents. The goal of asphalt recycling agents is to reintroduce the properties lost in bitumen and asphalt during aging such as penetration, softening point, viscosity, ductility, cohesion and adhesion to aggregate, reducing the performance of asphalt and requiring its replacement. The purpose of this study is to observe the chemistry of bitumen aging and the effects of recycling agents may have in reversing it. Fourier transform infrared spectroscopy (FTIR)-attenuated total reflectance (ATR) was used to analyse the bitumen aging and regeneration in terms of the evolution of carbonyl, sulfoxide and other bands. FTIR-ATR microscopy was used to study the distribution of these bands between the aggregates in order to understand the remobilization of the old asphalt (RAP) by the recycling agents through observing their penetration into the RAP. A method for aging bitumen and mastic in a ventilated oven was developed. An increase in C = O and S = O indices was observed with aging, plateauing after 7d

Methods for Analyzing the Chemical Mechanisms of Bitumen Aging and Rejuvenation with FTIR Spectrometry

WOS:000381366300017International audienceThe recycling of asphalt is a process where old pavement is broken up and used as reclaimed asphalt pavement (RAP) in new asphalt pavement, often with the aid of recycling agents. The goal of asphalt recycling agents is to reintroduce the properties lost in bitumen and asphalt during aging such as penetration, softening point, viscosity, ductility, cohesion and adhesion to aggregate, reducing the performance of asphalt and requiring its replacement. The purpose of this study is to observe the chemistry of bitumen aging and the effects of recycling agents may have in reversing it. Fourier transform infrared spectroscopy (FTIR)-attenuated total reflectance (ATR) was used to analyse the bitumen aging and regeneration in terms of the evolution of carbonyl, sulfoxide and other bands. FTIR-ATR microscopy was used to study the distribution of these bands between the aggregates in order to understand the remobilization of the old asphalt (RAP) by the recycling agents through observing their penetration into the RAP. A method for aging bitumen and mastic in a ventilated oven was developed. An increase in C = O and S = O indices was observed with aging, plateauing after 7d

Contribution à la maîtrise de la qualité des parements de béton

TOULOUSE3-BU Sciences (315552104) / SudocSudocFranceF

Evaluating concrete surfaces using an image analysis process

International audienceThis study concerns the assessment of non-coated concrete surfaces in civil engineering structures and buildings. Imaging is used as an objective tool for evaluation of the surfaces. Because images of surfaces taken under different conditions of illumination are difficult to compare, this paper presents a method suggested by the building firm GTM Construction and the laboratory LMDC for obtaining images of luminance L∗ simulated for one standard illuminant (D65). Concrete surfaces can be qualified with respect to uniformity of tint and distribution of surface bubbles. The process described is based on image analysis. Not only can the results be compared with current standards, but the method also gives access to additional, accurate information such as the distribution of defects and the size of surface bubbles. This method is already applied on building sites for experts’ assessments and in the laboratory for the study of the parameters influencing surface quality

Contribution à la maîtrise de la Réaction Alcali Silice par ajout de fines de granulats réactifs dans le béton

TOULOUSE-INSA (315552106) / SudocSudocFranceF

Investigation on Parameters Affecting the Effectiveness of Photocatalytic Functional Coatings to Degrade NO: TiO2 Amount on Surface, Illumination, and Substrate Roughness

WOS:000412573100001International audienceThis paper deals with the degradation of NO by photocatalytic oxidation using TiO2-based coatings. Tests are conducted at a laboratory scale through an experimental setup inspired from ISO 22197-1 standard. Various parameters are explored to evaluate their influence on photocatalysis efficiency: TiO2 dry matter content applied to the surface, nature of the substrate, and illumination conditions (UV and visible light). This article points out the different behaviors between three kinds of substrates which are common building materials: normalized mortar, denser mortar, and commercial wood. The illumination conditions are of great importance in the photocatalytic process with experiments under UV light showing the best results. However, a significant decrease in NO concentration under visible light is also observed provided that the TiO2 dry matter content on the surface is high enough. The nature of the substrate plays an important role in the photocatalytic activity with rougher substrates being more efficient to degrade NO. However, limiting the roughness of the substrate seems to be of utmost interest to obtain the highest exposed surface area and thus the optimal photocatalytic efficiency. A higher roughness promotes the surface contact between TiO2 and NO but does not necessarily increase the photochemical oxidation

A critical discussion on rebar electrical continuity and usual interpretation thresholds in the field of half-cell potential measurements in steel reinforced concrete

International audienc

Determination of the performance and damage to asphalt of bio-sourced asphalt release agents (ARAs) Part II: evaluation of biodegradable products for use as ARAs and bitumen removers (BRs)

WOS:000373963700025International audienceAsphalt release agents (ARAs) are used for reducing the adherence of asphalt residue to tools used for asphalt mix production, while bitumen removers (BRs) are used for cleaning the asphalt residue from the tools after their use. In order to be able to formulate well performing and safe bio-based ARAs and BRs, the performance, safety and chemistry of the currently available bio-degradable ARAs and BRs from both French and American construction industry were analysed. This provided insight into how ARAs and BRs functioned, insight that is as of now, not available. In addition to these, biodegradable short-chain esters were also tested. The testing of the damage to asphalt pavement by ARAs and BRs and of the quantification of their performance, were developed in Part I of this article. In this paper, gas chromatography examined the chemical composition of the agents while Fourier transformed infrared spectrometry was used to chemically investigate the agents' chemical modification of the bitumen. It was found that commercial ARAs can be classified by their functioning as either surfactants or softeners. Additionally, it was found that short-chained esters are very effective as BRs