Urban water management requires further clarification about pollutants in storm water. Little is known about the release of organic additives used in construction materials and the impact of these compounds to storm water runoff. We investigated sources and pathways of additives used in construction materials, i.e., biocides in facades' render as well as root protection products in bitumen membranes for rooftops. Under wet-weather conditions, the concentrations of diuron, terbutryn, carbendazim, irgarol 1051 (all from facades) and mecoprop in storm water and receiving water exceeded the predicted no-effect concentrations values and the Swiss water quality standard of 0.1 microg/L. Under laboratory conditions maximum concentrations of additives were in the range of a few milligrams and a few hundred micrograms per litre in runoff of facades and bitumen membranes. Runoff from aged materials shows approximately one to two orders of magnitude lower concentrations. Concentrations decreased also during individual runoff events. In storm water and receiving water the occurrence of additives did not follow the typical first flush model. This can be explained by the release lasting over the time of rainfall and the complexity of the drainage network. Beside the amounts used, the impact of construction materials containing hazardous additives on water quality is related clearly to the age of the buildings and the separated sewer network. The development of improved products regarding release of hazardous additives is the most efficient way of reducing the pollutant load from construction materials in storm water runoff.
There is increasing concern about diffuse pollution of aquatic systems by biocides used in urban areas. We investigated sources and pathways of biocides significant for the pollution of storm water runoff. Main sources seem to be building envelopes, i.e. facades (paints, plasters) and roof sealing membranes. First results from a defined urban catchment drained by a separated sewer system without any agricultural activities reveal a substantial occurrence. Even after the first flush, concentrations of terbutryn, carbendazim, mecoprop as well as Irgarol 1051 and its metabolite exceeded the Swiss water quality standard of 0.1 microg/L. In laboratory experiments, leaching of mecoprop used as a root protection agent in bitumen sheets for roof waterproofing was determined. The concentrations differed in 16 different sheets two orders of magnitude, depending on the product composition. Using optimized products, it is expected to be the most efficient and sustainable way to reduce the environmental impact. To understand transport dynamics and environmental risk, further storm water events will be analyzed. Based on the ongoing project URBIC, first measures will be proposed to limit the release to surface and ground water.
This paper contains a short state of the art overview on bituminous plug joints (BEJ) in Switzerland. Such BEJs are of particular interest because of their noise reduction properties. BEJs designed for joint movements up to 100mm were investigated in the lab and field as a basis for guidelines by the Swiss Federal Road Office. Special test procedures including gel permeation chromatography (GPC), testing of adhesion between joint filling material and adjacent pavement, rutting performance testing with model mobile load simulator MMLS3 as well as cold temperature movement capacity testing with a joint movement simulator are presented. In addition, longterm field performance of standard BEJs for small joint movements and special wide BEJs, some of them containing moving aids for large joint movements, are discussed. It was found that the tools and requirements elaborated in the Swiss guidelines are suited to reduce the risk of BEJ failure. It became also apparent that placing technology and climate play a significant role in achieving well performing BEJ for short and large joint movements.
Four-point bending beam tests are applied to investigate the bending behavior of asphalt composites strengthened by grid reinforcements made of carbon, glass, and polyester fiber grids. Both experimental and analytical predictions are compared considering the deflection behavior of carbon grid-reinforced beams. This study especially shows significant structural improvement and better crack resistance of asphalt composite beams by carbon grids. Temperature and loading rate dependencies are also evaluated and compared for both reinforced and unreinforced asphalt composite beams. The maximum bending forces of carbon grid-reinforced beams significantly decrease with decreasing loading rate and increasing the temperature. The deflection behavior of asphalt composite beams reinforced by carbon grids is reasonably predicted using a bilinear damage-based model and a viscoelastic beam theory. The layer-parallel direct shear test is conducted for investigating the interlayer shear behavior of asphalt composite beams.
The aim of the study was to understand how the Tpeel strength of heat-welded seams in polymer-modified bituminous roofing membranes depends on the welding method and on the material properties.Seam samples of ten different commercial products, three of Atactic Polypropylene (APP)-modified bitumen and seven ofStyrene-Butadiene-Styrene copolymer (SBS)modified bitumen, were prepared by different welding methods with different heating media, i.e. hot air or gas torch, welding speed and weight of pressure roller joining seams. The welding conditions were precisely controlled during the preparation, and the temperature in the seam sample was measured.T-peel tests were carried out at 23°C and at -10°C on specimens cut out from each heat-welded sample to measure the T-peel strengths. The fracture propagation during T-peel testing was studied visually. Some seam specimens were also studied using microscopy.In order to identify the material properties and differences in the material compositions influencing the seam strengths, each product was characterised by different chemical and thermal methods, which were described in recently published reports [1,2].It was concluded that the choice of welding speed and pressure weight for the optimum design of welding machine should make reference to the thermal properties, such as specific heat, and to the rheological properties, such as viscosity.
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