Bitumen Roof Research Articles

Drone remote sensing to define heat exchange between urban surfaces and stormwater runoff

ABSTRACT Urban water bodies are often subject to high runoff temperatures from heat exchange between rainfall and urban surfaces; however, this process can be difficult to define due to the complexity of spatially heterogeneous urban areas. This research seeks to improve our understanding of heat exchange in urban stormwater runoff by integrating in situ measurements of runoff temperature with land surface temperature data captured in high spatial resolutions by a drone. To do so, this study monitored four urban catchments in Milwaukee, WI that are dominated by different land surfaces (concrete parking lot, asphalt road, black bitumen roof, and grass). Results indicate that land surface temperature was variable among common land surface types (1.34–2.24 °C), with higher variations in surfaces subject to foot and vehicular traffic. In addition, the temperature of runoff from impervious surfaces responded differently between buildings and those with a ground subsurface, with higher event mean temperatures from concrete (21.4 °C) and asphalt (21.9 °C) ground surfaces as compared with the bitumen roof (19.8 °C), despite similar initial surface temperatures. Ultimately, these outcomes demonstrate how drone remote sensing of land surface temperature and in situ monitoring can be integrated to understand heat exchange processes in urban stormwater runoff.

Quality of Harvested Rainwater from a Green and a Bitumen Roof in an Air Polluted Region

A one-year study was conducted to evaluate the impact of air pollution and roof coating on runoff quality. An existing 440 sq meter bitumen roof of a single-story building was coated with an extensive green roof layer on one half. Rainfall and runoff samples from both roofs were collected during 11 rainfall events after the separation of the first flush. The study monitored several key parameters, including pH, electrical conductivity (EC), turbidity, chemical oxygen demand (COD), ammonium nitrogen, nitrate nitrogen, and phosphates. The study revealed that both types of roofs altered the rainfall quality, but the changes caused by the green roof were more substantial. Although the retention of runoff from green roofs has a widely acknowledged positive impact on collecting systems, our study shows that green roofs also result in a 7.5-fold increase in COD concentrations, a 5.4-fold increase in the sum of ammonium and nitrate nitrogen, and a 2.3-fold increase in phosphates compared to bitumen roofs. A clear link between the quality of rainwater/runoff and air pollution was not established. The study's findings will aid in the development and management of local rainwater harvesting systems and enhance global understanding of the primary quality parameters of various roof types, particularly in regions with air pollution. Doi: 10.28991/CEJ-2024-010-05-015 Full Text: PDF

Use of Rubber Crumb Obtained from Waste Car Tires for the Production of Road Bitumen and Roofing Materials from Residues of Ukrainian Oil Processing

The process of modifying road bitumen obtained from the residues of Ukrainian oils processing with rubber crumb has been studied. The dependence of the softening temperature, ductility, penetration, and elasticity of the three-component bituminous composition “bitumen : linseed oil : rubber crumb” on its formulation has been examined. Based on the mentioned composition a new type of cold-applied bitumen roofing has been developed. A process flow diagram for the production of modified bitumen and special-purpose bituminous composition has been developed.

Increasing solar panel output with blue-green roofs in water-circular and nature inclusive urban development

With an increasing demand for climate resiliency, water sensitivity, nature inclusiveness and energy efficiency in dense urban environments, the call for layered and multifunctional use of rooftops is rising. Vegetated roofs combined with Photo-Voltaic (PV) installations are an example of multifunctional and more effective use of available space, and well-irrigated systems could have an enhanced cooling effect. This research investigated a blue-green capillary irrigated solar roof with grey (shower-) water suppletion, with a constructed wetroof for grey water purification. Two full-scale commercial PV systems on twin rental apartment blocks in Amsterdam were analyzed, on a blue-green roof (BGR) versus a bitumen roof (BiR). The energy output, PV panel temperature, relative humidity and air temperature under the panels were monitored during 5 warmer months (June–October 2022). On average, a solar panel on the BGR is expected to produce 4.4% more energy than a solar panel on the BiR at similar irradiation. A clear difference in panel temperature on the roofs is only seen when the surface temperature of the roofs differs by at least 4.64 °C. Otherwise, other factors such as wind or albedo have probably more influence on the PV panel temperature and thus on PV power output.

Hydrologic Effectiveness and Economic Efficiency of Green Architecture in Selected Urbanized Catchment

This paper presents a numerical assessment of the influence of green roofs applied in the urbanized catchment on the rainwater outflow hygrogram as well as costs and economic efficiency analysis of the proposed green architecture application. The campus basin of the Lublin University of Technology, Poland, was selected as the object of the study. Three variants of extensive green roof applications were designed. The numerical model of surface runoff was developed in US EPA’s SWMM 5.2 software. The simulations were performed for three different rainfall events of various intensities and durations. The cost efficiency of the proposed green architecture was assessed by the Dynamic Generation Costs indicator, while economic effectiveness was tested by Benefits–Costs Ratio and Payback Period determined for all assumed variants. The determination of economic efficiency indicators was based on investment and maintenance costs estimation, assumed discount rate, and time duration of assessment. Results of numerical calculations showed up to 16.81% of peak flow and 25.20% of runoff volume reduction possibly due to the green roof application. All proposed variants of green roof applications in the studied urbanized catchment were assessed as generally profitable due to possible financial benefits related to heating and cooling energy savings and avoiding periodical change of bitumen roof cover.

Retention of snowmelt and rain from extensive green roofs during snow-covered periods

Abstract Green roofs are a popular way to include nature in an urban environment. A reduction in stormwater runoff peaks and volumes are among the benefits one can expect. How is runoff from green roofs in the cold and snow-covered part of the year, when growth media freeze, plants are dormant and covered with melting snow? This paper investigates 11 years of runoff from three green extensive roofs in Oslo, Norway. Precipitation through the snow-covered period (SCP) was approximately one-third of the annual precipitation (970 mm). When runoff from green roofs is compared to runoff from a non-vegetated bitumen roof, retention of 16–31% is seen through the SCP, depending on the drainage system, fabric, soil quality, and depth. The difference in buildup did not influence the detention of the largest runoff intensities. Dampening the runoff happened even though the substrate was saturated. According to the soil moisture sensors, the capacity of the roof with the highest water retention could be increased even more if drainage could be restricted. The runoff from the bitumen roof always exceeded the runoff from green roofs. As a result, harmful inundation may be reduced in a part of the year when infiltration is restricted due to frost.

Synergistic fire‐retardancy properties of melamine coated ammonium poly(phosphate) in combination with rod‐like mineral filler attapulgite for polymer‐modified bitumen roofing membranes

SummaryA novel intumescent (carbonization, acid donor and foaming) fire retardant that mimics carbon nanotubes was introduced into bitumen roofing and characterized using cone calorimetry as the main analytical tool. The experimental results indicate that 18% (by mass) attapulgite mineral (ATTP) mixed with base bitumen decreased the peak heat release rate per unit area (pHRRPUA) by 10%. Further, incorporation of melamine coated ammonium polyphosphate (MAPP) decreased the pHRRPUA by 52% and a mixture of these (3:1, ATTP:MAPP) decreased the pHRRPUA by 25% as compared to adding CaCO3 as a filler. The residual mass loss after the cone test was also improved with up to 3%. The indication of a positive synergistic flame retardant effect of the ATTP‐MAPP mixture is supported by thermogravimetric analysis. The addition of this rod‐like mineral improved the general fire retardant properties of the base bitumen and increased the viscosity. Therefore, the polymer‐modified bitumen with both fire retardant and rheological properties (providing mechanical strength) is a promising novel approach in the design of bitumen roofing membranes.

Flammability Characteristics of Green Roofs

Assessing the fire risk of vegetated roofs includes the determination of their possible contribution to fire. Green roof components such as plants and growing media are organic materials and present a fuel that can catch and support the spread of fire. The flammability characteristics of these components were analyzed and compared to a typical roof covering. Growing media with 15% of organic matter were tested using cone calorimeter apparatus. The fuel load and heat release rate of the growing media were measured in both moist (30%) and dry conditions. It was observed that growing media in a moist condition do not present a fire risk, reaching a maximum heat release rate of 33 kW/m2. For dry substrates, a peak heat release rate of 95 kW/m2 was recorded in the first minute, which then rapidly decreased to 29 kW/m2 in the second minute. Compared to a typical bitumen roof membrane, the green roof showed a better fire performance. The literature data report more severe results for plant behavior, reaching peak heat release rates (HRRs) of 397 kW/m2 for dried and 176 kW/m2 for a green material. However, a rapid decrease in HRR to much lower values occurs in less than 2 min. The results also show that extensive and intensive types of green roofs present 22% and 95% of the additional fire load density when installed on a modified bitumen membrane, 19.7 and 85.8 MJ/m2, respectively.

Битумно-полимерные гидроизоляционные материалы с использованием нефтешламов

Битумно-полимерные гидроизоляционные материалы с использованием нефтешламов

The impact of bitumen roofing production waste (BTw) on cement mortar properties

This paper is aimed to show the impact of bitumen roofing production waste (BTw) on the properties of cement mortars in terms of mineral composition, microstructure, setting rate, physical and mechanical properties and durability (water absorption, freeze-thaw resistance). To this aim, mortar specimens were manufactured by replacing 0%, 2%, 4%, and 6% of natural sand by weight with BTw. The main results show that BTw slightly accelerates cement hydration and 4% is the best content of BTw to be valorised in mortars. In this case, compressive strength, density and ultrasound pulse velocity are comparable to the control mortar (0% BTw content) but capillary water absorption decreases and flexural strength increases. Moreover, at this dosage, the forecasted freeze-thaw resistance of mortars increases considerably (~30%).

The Impact of Bitumen Roofing Production Waste (BTw) on Physical Mechanical Properties of Concrete

This article presents how concrete properties would change if part of a coarse aggregate (granite crushed stone) were replaced with bitumen roofing production waste (BTw). BTw is a huge ecological problem because these wastes are generated in large quantities when replacing old bitumen-based roof tiles. Wastes are also produced during the production of bituminous roof coatings. Usually BTw are stored in landfills or it is attempted to use/dispose them in the production of asphalt concrete. There are very few works which analyse the impact of BTw on the properties of cement materials, although the impact of these wastes on the properties of cement materials could be beneficial because BTw consist of aggregate, granules, bitumen and fibers. In order to use BTw, standard concrete samples were first formed, then 5/16 granite fraction was replaced with BTw in amounts of 2%, 4% and 6% by weight The amounts of limestone Portland cement, fine aggregate (sand), water and superplasticizer in the concrete mixtures were constant. The new generation of superplasticizer based on polycarboxylates was used in mixtures. The following concrete properties were identified and analyzed: density of the mixture, flowability, density of concrete samples, water absorption, compressive strength, forecasted frost resistance, and microstructure studies were conducted as well. The results of the studies showed that BTw can be used in small amounts, i. e. up to 6%, then the density of the samples slightly decreased (by 2.4%) and water absorption increased (by 0.7%). Compressive strength, after replacing 2% granite crushed stone, decreased by 2.4%. However, gradual addition of the amount of BTw resulted in more closed pores that improved the frost resistance of the concrete. When 6% of bulk filler was replaced with BTw, closed porosity, compared to control samples, increased by 54% and forecasted frost resistance - by 26%. Microstructure analysis showed that with 6% BTw a dense cement stone structure was formed, showing the hydrates of portlandite and CSH.

Identification of a water quality indicator for urban roof runoff

Control and management of stormwater volume and water quality is an important concern in Iran and there is little or insufficient scientific information in assessing domestic roof harvested rainwater quality by suitable indicators. The objectives of this study were (1) to determine water quality factors which vary significantly with roof materials and first flush, (2) to select an indicator from these factors that can be used for water quality monitoring in roof runoff and (3) to find out whether a relationship exists between the resulting roof runoff water quality (WQI) and air quality parameters. Factor analysis (FA) was used to identify water quality factors and discriminant analysis (DA) was used to determine the factors and an indicator most sensitive to first flush and posterior roof runoff within mosaic tile and bitumen roofing material. Therefore, seven water quality parameters were measured in 28 runoff samples collected from two mosaic tile and bitumen roofs in seven rainfall events. FA identified three factors that explained 82.8% of the variation in water quality parameters. Discriminant analysis selected phosphate and nitrate as the most sensitive parameters in domestic roof harvested rainwater. Correlation analysis of the resulting roof runoff WQI with the air quality parameters showed that the indicator has significant correlation with most air quality parameters. Forward stepwise general regression model revealed that the roof water quality indicator values were explained by air SO2. This suggests that domestic roof harvested rainwater quality could be controlled by air quality characteristics.

Environmental benefits of green roofs on microclimate of Tehran with specific focus on air temperature, humidity and CO2 content

The main objective of this study is to evaluate the genuine effect of green roofs on Tehran's microclimatic conditions and air quality parameters. Two buildings with different roof covers (green and bitumen roof) were selected and air temperature, relative humidity and carbon dioxide concentration data loggers were installed on both of them in two different conditions. Also, the effect of roofs materials on indoor air temperature, heat exchange and energy consumption of each building was assessed by installing internal thermometer inside the rooms to study the indoor thermal conditions of the buildings. Results demonstrated that average air temperature above the green roof was 3.06 and 3.7°C cooler than that of reference roof inside and outside the screen box, respectively. Also, RH above the green roof was 11.94 and 8.46% higher than the reference roof inside and outside the screen box, respectively. Furthermore, the average air CO2 concentration inside and outside of the screen box above the green roof during the studied period was 27.98 and 20.71ppm lower than the reference roof. Similarity, interior spaces of the buildings with green roof showed lower measured air temperature than buildings with bitumen roof.

Will cool roofs improve the thermal performance of our built environment? A study assessing roof systems in Bahrain

A number of international campaigns have recently proposed the use of cool roofs worldwide in order to cope with the summer urban heat island (UHI) effect. This work investigates cool roof strategy and examines the potential of such a strategy for Bahrain. Full-scale measurement, meteorological modelling and thermal simulation of five standard roofs were performed during particular summer days due to the high intensity levels of solar irradiation. This work shows that the light tile roof and metal decking are relatively cooler and more comfortable than others and that the maximum reduction in heat gain occurs for a light tile roof with thermal insulation materials. Nevertheless, without insulation the cooling load is increased by only 1.3%. This percentage seems not to be cost-effective where economics and building construction are concerned. In contrast, the reduction percentage due to the use of thermal insulation in the case of dark tile roof, felt bitumen roof and screed roof increases to 5–7%, which is more cost effective. This work concludes that the cool roof strategy is the most cost-effective for the hot climate of Bahrain, which has a long cooling season. With the current levels of urban development in Bahrain, cool roofs can reduce UHI intensity and building cooling loads, lowering demand for electricity and greenhouse gas emissions from power plants. To avoid any negative consequences from using this strategy, however, trade-offs between urban mitigation and adoptation strategies and complementary technologies should be accounted for in future urban development plans.

The Cost Effectiveness of Alpha SPF Roofs: Casa View Elementary School Roofing Case Study

The performance of the Alpha Sprayed Polyurethane Foam (SPF) roofing system is perceived as not an economical option when compared to a 20-year modified roofing system. The Dallas Independent School District (DISD) is replacing the existing Alpha SPF roof systems with new roof systems rather than recoating the existing systems at a cost that is 100% more than the recoating costs. The DISD is in a heavy hail area, and the proven hail resistance of the Alpha SPF roof system is an additional benefit for DISD who is self-insured. The Casa View Elementary School roof system was installed with a Neogard Permathane roof system in 1987. This roof was hail tested with ten drops from 17 feet 9 inches of 1-3/4-inch steel ball (9 out of 10 passed) and three drops from 17 feet 9 inches with a 3-inch diameter steel ball (1 out of 3 passed). The analysis of the passing and failing core samples show that the thickness of the top and base Alpha SPF coating is one of the major differences in a roof passing or failing the FM-SH hail test. The current potential cost savings of purchasing a 61,000 square feet Alpha SPF roof versus modified bitumen roof is approximately $610,000 for DISD. The past hail tests on Alpha SPF roof systems show high customer satisfaction (9.8 out of 10) and an over 40-year service life after a $6.00/SF recoat.

Comparative microclimate and dewfall measurements at an urban green roof versus bitumen roof

Urban green roofs are discussed as a local climate adaptation measure to limit surface warming and increase evaporative cooling by vegetation in urban environments. A five month measurement campaign was conducted to observe surface and air temperatures as well as dewfall dynamics and amounts on an urban green and co-located bitumen roof. Measurements were performed in the period from August to December 2012.Surface temperatures indicated differences of up to 17.4 K, which lead to measurable air temperature differences (ΔTA) at a height of 0.5 m above roof level. During August afternoons (3 pm) the green roof air temperature (TA) drops below TA of the bitumen roof by up to 0.7 K on average. By using a linear regression based approach differences in sensible turbulent heat flux densities (QH) between green and bitumen roof of 200 W m−2 on a hot day with 30 °C and wind velocities of 2 m s−1 were estimated.During the measurement campaign a total of 60 and 52 dew events were observed on the bitumen roof and the green roof, respectively. At both urban sites the number of dewfall events was distinctly smaller compared to the rural site (94 events). Roof dewfall turned out to be a negligible source in the green roof water balance compared to precipitation amounts. Inhibited dewfall on roofs could be one important factor for the phenomenon of urban moisture excess since roofs represent a high fraction of urban surfaces.

A Technical and Economical Assessment of Replacement of Coarse Aggregate By Waste Tyre Rubber In Construction

A Technical and Economical Assessment of Replacement of Coarse Aggregate By Waste Tyre Rubber In Construction

Best Value Case Study for Cold Storage Facility in Miami, Florida

A cold storage facility had been reroofed in 2003 (investment of $600,000) that required the removal of existing insulated roof and replaced with a 20 year modified bitumen roof. After six years, the facility posed a safety hazard due to the ice formations inside the cold storage facility. The source of the problem was not known. The traditional process of using a professional designer, a certified contractor, receiving a manufacturer’s warranty, and having the roof inspected by the local government inspector could not assist the owner and the FM resolve the complex problem. The facility manager (FM) decided to utilize a non-traditional Best Value (BV) Performance Information Procurement System (PIPS) to identify and resolve the problem. The main difference of the system is that the best value vendor and not the owner determines the final scope. This paper documents the BV PIPS approach and the resulting performance. An inspection five years later verified the performance of the Best Value approach and showed the value of the installed sprayed polyurethane (SPF) roofing system.

Runoff and vegetation stress of green roofs under different climate change scenarios

Green roofs are efficient tools to improve life quality in densely populated areas. The contribution to the reduction of stormwater runoff and the heat-island effect may even augment with climate change. In this study, impacts of climatic changes on vegetation drought stress and stormwater retention of two green roof types (one with sedum-moss vegetation, one with grass-herbs vegetation) and a standard bitumen roof were assessed using a water balance model (GreenRoof). A case study of the Flemish region in Belgium was done, but the study can be representative for temperate maritime climates worldwide. Local weather data for the 2050s were generated with the LARS-WG weather generator based on climate scenarios from two multi-model ensembles of respectively 15 global and 9 regional climate models. Under the projected differences in precipitation and evaporating power of the atmosphere, runoff was expected to decrease in summer and to increase in winter on all roof types. Grass-herb green roofs could reduce runoff more than sedum-moss green roofs, but were more sensitive to increased drought stress. Both green roof types were shown to remain a valid option for runoff reduction in urban areas as compared to bitumen roofs, mainly in summer. The benefit of green roofs can increase under climatic changes but increased vegetation stress urges reconsideration of green roof design and vegetation choice to obtain an optimal runoff reduction and vegetation survival.

Comparison of roof runoff water originated from two types of roof material

The present study demonstrates the differences in the quality of roof runoff from bitumen shingle and galvanized iron test roofs. Average first flush conductivity was found to be 113.6 μS/cm in bitumen roof runoff as opposed to 45.4 μS/cm in galvanized iron roof runoff. The chemical oxygen demand of bitumen roof runoff was one order of magnitude higher than that of galvanized iron roof runoff, which could be attributed to the material and coarse surface of the former roof. The suspended solid content of the two runoffs there were, in average, identical.