Shell Bitumen - WAM Field Test Results Italy - Inspiring Solutions for ...

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Emission and occupational exposure at lower asphalt production and laying temperatures M. Lecomte Shell Bitumen, 307 rue d’Estienne d’Orves, 92708 Colombes, Paris, France F. Deygout Shell Bitumen, RD3, BP97, 76650 Petit Couronne, France A. Menetti Contech, Italy Summary It is well known that reducing asphalt production temperatures has significant environmental benefits on emissions, occupational exposures and energy consumption. The hot mix asphalt industry has been aware of this for many years. The biggest challenge however has always been to achieve adequate asphalt mixture quality at lower or ambient operating temperatures. In recent years, new production processes at temperatures between 80 - 120°C have attracted much interest because of the possibility to approach or even obtain hot mix quality and having reductions in energy consumption, emissions and occupational exposures. Results of recent measurements on a site in Florence in Italy show that decrease in temperature offers a dramatic reduction in greenhouse gases emission and a considerable reduction of fume emissions and workers exposure, together with a 30% energy reduction. This confirms the great potential of this solution for the environment. 1. Introduction Shell Bitumen is very active in the development of new technologies and in investigations to properly quantify the environmental benefits [1-5]. This paper describes the results of recent emission and exposure studies carried out at Conglobit during the production of their new asphalt mixture, Greenfalt, manufactured at low temperatures and developed on the basis of the Shell patented warm asphalt mixture (WAM) technology 1 using foam [6]. It must be understood that in all cases (hot and warm production) the values determined are well below any occupational exposure or environmental limit. This clearly demonstrates that both hot mix and WAM Foam production are fully acceptable from an occupational and environmental point of view. In October 2006, during a trial on the high speed road Firenze-Pisa-Livorno in Italy, several air pollutants (CO 2 , CO, NO x , SO 2 , TOC and dust) emitted by the chimney of the mixing plant were measured by Det Norske Veritas AS. Simultaneously, emission measurements were carried out at three positions in the asphalt mixing plant. During the asphalt laying and compaction operations, the paving crew was equipped with fume collection devices for exposure measurements. 1 WAM is a Shell trademark 1/11
For both emissions and exposures, fume analysis was performed to determine the total aerosols, the organic aerosols (Benzene Soluble Fraction), the gaseous fraction and specific polycyclic aromatic compounds. All measurements were performed during the production of the conventional hot mixtures and the production of Greenfalt. The mixing temperatures were 180°C for the conventional hot mixture and 120 to 125 °C for the WAM Foam. The productions were carried out on different days of the same week, in the same mixing plant, with the same testing devices and in similar weather conditions in order to get a set of fully comparable data. In addition, energy consumptions for the two different productions were compared. 2. Studies in Florence, Italy Work was conducted on 25 and 27 October 2006 in Florence at a mixing plant that was modified to produce asphalt according to the WAM foam process. The hard bitumen used for WAM was a 20/30 pen grade (EN12591 – Table 1) and the soft bitumen was a V10000 grade (EN12591 – Table 3). The objectives of the study were the following: To determine personal exposures for applications for the road contractor Conglobit. Conglobit uses the WAM Foam process to produce and lay asphalt mixtures under the name "Greenfalt". To compare, under field exposure conditions, the type of emissions using Greenfalt with those using HMA. To collect and compare emission values from mixing operations in the asphalt plant during WAM and HMA production. Exposures to particulate matter were determined and compared with Italian Occupational Exposure Limits (OEL) for bitumen fumes (petroleum bitumen CAS number 8052-42-4). Some countries, such as Italy in 2003, have adopted the American Conference of Governmental Industrial Hygienists (ACGIH) recommendations [7] into national legislation. In January 2000, ACGIH changed its Recommended Exposure Limits (REL) for bitumen fumes. The limit was 5 mg/m 3 measured as total aerosols (mineral and organic). The latest REL is 0.5 mg/m 3 measured as benzene-soluble aerosol of the inhalable fraction, i.e. the organic fraction of total aerosols. Total aerosols are measured using a closed-faced 37-mm cassette equipped with a PTFE filter, which is a "total aerosol" sampler (breathable fraction). Total organic aerosols are then extracted and quantified (Benzene Soluble Fraction or BSF). Note that the inhalable fraction is regarded as similar to BSF for this work. Sampling durations for HMA and WAM were between 3 and 4 hours which was adapted to obtain more than the minimum quantity (BSF > 0.1 mg/m 3 ) required by NIOSH 5042. The positions of the samplers are indicated in Picture 1. Two samplers close to the pugmill; due to the observed saturation of the filters in the case of hot mixture production, a third filter was added with a 60 minutes sampling time. No saturation was observed in the case of WAM Foam. Two samplers set up at the top of the discharge hoppers. Sampler(s) at the discharge point. Static sampler, about 50 m away from the mixing plant. 2/11
Page 1: ENGLISH SPANISH GERMAN CHINESE FREN
Page 5 and 6: Picture 2 Picture 3 Two static samp
Page 7 and 8: Figure 1 CO 2 emission levels at th
Page 9 and 10: 3.3 Results and discussion on emiss
Page 11 and 12: 5. PAHs in BSF The PAH concentratio

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