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Bradley D Rowe - One of the best experts on this subject based on the ideXlab platform.
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green roof substrates effect of recycled crushed porcelain and Foamed Glass on plant growth and water retention
Urban Forestry & Urban Greening, 2016Co-Authors: Mert Eksi, Bradley D RoweAbstract:Abstract A study was conducted in a controlled environment greenhouse to examine the potential of recycled crushed porcelain and Foamed Glass for use as a component of green roof substrates. Porcelain and Foamed Glass substrates were compared to heat-expanded shale which served as the control. Each finished substrate was analyzed per German FLL guidelines to determine granulometric distribution, bulk density, total porosity, water-holding capacity, saturated hydraulic conductivity, pH, soluble salts, organic matter content, and cation exchange capacity. Both substrates met FLL Guidelines except the porcelain substrate contained a greater percentage of larger particles and its maximum water holding capacity was lower than recommended. Two plant species were used in the study, Sedum album (stonecrop) and Ocinum x citriodolum (lemon basil). Data collected included substrate volumetric moisture content (VMC), plant growth, biomass accumulation, and plant stress as measured by chlorophyll fluorescence. Substrate VMC was generally greater in shale than in Foamed Glass or porcelain. At the end of the study plant growth index was greatest for stonecrop growing in shale, but there was no difference among the substrates for basil. However, plants of both basil and stonecrop accumulated the most total biomass when grown in shale. It is probable that water retention could be improved for both recycled crushed porcelain and Foamed Glass if more attention was paid to reducing particle size during processing. If so, then they may perform equal to heat expanded shale when incorporated into green roof substrates. In the case of porcelain, its use could divert some waste from landfills and greatly reduce the embodied energy required to construct a green roof.
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the suitability of crushed porcelain and Foamed Glass as alternatives to heat expanded shale in green roof substrates an assessment of plant growth substrate moisture and thermal regulation
Ecological Engineering, 2016Co-Authors: Jason M Matlock, Bradley D RoweAbstract:Abstract The suitability of two materials, Foamed Glass and crushed porcelain, as substrates for single course extensive green roofs was investigated. Both of these materials were produced from bulk waste intended for disposal in a landfill. The candidate materials were compared to a commercially available substrate made from heat-expanded shale by evaluating commonly measured physical properties, plant development, substrate moisture, and subsurface temperature. Physical properties were measured in a lab setting and all other metrics were taken from outdoor green roof platforms. Total plant coverage in both porcelain and Foamed Glass was equivalent to expanded shale on 5 of the 6 dates measured over two growing seasons. Substrate moisture and temperature were observed during the second season. Moisture content of both the porcelain and Foamed Glass was either equivalent to or greater than that of the expanded shale throughout the season. Subsurface temperatures were cooler in the porcelain and Foamed Glass than the expanded shale during the daytime for the majority of the second season. Variation in daily temperatures in the porcelain was significantly lower than the expanded shale when plant coverage was below 50%. Overall, both candidate materials were found to be suitable for use in extensive green roof applications.
Hongling Zhou - One of the best experts on this subject based on the ideXlab platform.
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influence of ceo 2 addition on the preparation of Foamed Glass ceramics from high titanium blast furnace slag
International Journal of Minerals Metallurgy and Materials, 2018Co-Authors: Hongling Zhou, Keqin Feng, Changhong Chen, Zidi YanAbstract:Foamed Glass-ceramics doped with cerium oxide (CeO2) were successfully prepared from high-titanium blast furnace slag by one-step sintering. The influence of CeO2 addition (1.5wt%–3.5wt%) on the crystalline phases, microstructure, and properties of Foamed Glass-ceramics was studied. Results show that CeO2 improves the stability of the Glass phase and changes the two-dimensional crystallization mechanism into three-dimensional one. XRD analysis indicates the presence of Ca(Mg, Fe)Si2O6 and Ca(Ti, Mg, Al)(Si, Al)2O6 in all sintered samples. Added with CeO2, TiCeO4 precipitates, and crystallinity increases, leading to increased thickness of pore walls and uniform pores. The comprehensive properties of Foamed Glass-ceramics are better than that of samples without CeO2. In particular, the sample added with a suitable amount of CeO2 (2.5wt%) exhibits bulk density that is similar to and compressive strength (14.9 MPa) that is more than twice of Foamed Glass-ceramics without CeO2.
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effect of sintering temperature on the microstructure and properties of Foamed Glass ceramics prepared from high titanium blast furnace slag and waste Glass
International Journal of Minerals Metallurgy and Materials, 2017Co-Authors: Changhong Chen, Keqin Feng, Yu Zhou, Hongling ZhouAbstract:Foamed Glass-ceramics were prepared via a single-step sintering method using high-titanium blast furnace slag and waste Glass as the main raw materials The influence of sintering temperature (900–1060°C) on the microstructure and properties of Foamed Glass-ceramics was studied. The results show that the crystal shape changed from grainy to rod-shaped and finally turned to multiple shapes as the sintering temperature was increased from 900 to 1060°C. With increasing sintering temperature, the average pore size of the Foamed Glass-ceramics increased and subsequently decreased. By contrast, the compressive strength and the bulk density decreased and subsequently increased. An excessively high temperature, however, induced the coalescence of pores and decreased the compressive strength. The optimal properties, including the highest compressive strength (16.64 MPa) among the investigated samples and a relatively low bulk density (0.83 g/cm3), were attained in the case of the Foamed Glass-ceramics sintered at 1000°C.
Akira Nakajima - One of the best experts on this subject based on the ideXlab platform.
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low temperature preparation and machinability of porous ceramics from talc and Foamed Glass particles
Journal of The European Ceramic Society, 2009Co-Authors: Kiyoshi Okada, Fumihiko Ikawa, Toshihiro Isobe, Yoshikazu Kameshima, Akira NakajimaAbstract:Abstract Porous ceramics were prepared by firing mixtures of talc (Mg3Si4O10(OH)2) and Foamed Glass particles (ceramic balloons, CB) with and without LiCl as a sintering acid. The mixing ratios of the starting materials were talc:CB = 7:3, 8:2, 9:1 and 10:0, with additions of LiCl of 0, 2 and 5 mass%. The mixtures were formed into pellets and fired at 600–1000 °C. The pellets without LiCl showed very poor strength even when fired at 1000 °C but those containing LiCl were much stronger, even when fired at only 600 °C. The crystalline phases in these samples changed to enstatite (MgSiO3) at ≥ 700 °C by decomposition of the talc under the fluxing action of the LiCl. The resulting samples were machinable and easily cut and drilled. The cutting rate decreased with increasing bending strength, for example, from 105 mm2/s and 6.3 MPa to 50 mm2/s and 16.3 MPa, respectively. The drilling rate of the present sample was found to be only slightly less than Teflon (polytetrafluoroethylene, PTFE) but much faster than graphite, Glass ceramics, etc.
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water retention properties of porous ceramics prepared from mixtures of allophane and vermiculite for materials to counteract heat island effects
Ceramics International, 2008Co-Authors: Kiyoshi Okada, Toshihiro Isobe, Yoshikazu Kameshima, Shunsuke Matsui, Akira NakajimaAbstract:Abstract Porous ceramics for anti-heat island effect were prepared from mixtures of allophane and vermiculite (VA samples). Allophane and vermiculite which had been ground for 0.5–2 h was mixed in various mass ratios, formed into pellets by uniaxial pressing at 40 MPa, and heated at 600–800 °C to form porous ceramics. The large thermal expansion of the vermiculite upon explosive dehydration of interlayer water causes cracking of the pellets with higher vermiculite contents. However, this can be controlled by grinding the vermiculite prior to heating. Grinding the vermiculite for ≥2 h suppresses its expansion, enabling pellet samples with high vermiculite contents to be prepared without cracking. The bulk densities of samples prepared at 800 °C from vermiculite ground for 2 h decrease from 1.72 to 0.94 with increasing allophane content. The pore size distribution in these samples shows a distinct peak at about 1 μm irrespective of the mixing ratio. The number of smaller pores ( W a ) of the samples increases from 37 to 63% with increasing allophane content. This absorption rate is fast enough to absorb >90% of the W a within 1 min for samples of 10 mm O × 5 mm 3 size. By contrast, the release of the absorbed water is very slow, with 50% of the W a retained for ≥30 h in the VA samples at a relative humidity of 55% at 20 °C; this is slower than in pure allophane and much slower than in a reference sample of Foamed Glass (about 4 h). All these properties make the VA samples useful as water-retaining materials to combat “heat island” effects.
Yan-jun Du - One of the best experts on this subject based on the ideXlab platform.
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Engineering and environmental properties of Foamed recycled Glass as a lightweight engineering material
Journal of Cleaner Production, 2015Co-Authors: Arul Arulrajah, Farshid Maghoolpilehrood, Artit Udonchai, Monzur Imteaz, Mahdi M Disfani, Suksun Horpibulsuk, Yan-jun DuAbstract:Lightweight fill materials, including Foamed aggregates are increasingly being used in civil engineering and infrastructure applications. This research assessed the engineering properties of Foamed recycled Glass through a laboratory evaluation to ascertain this novel recycled material as a lightweight fill material in civil engineering applications. The engineering assessment included particle size distribution, particle density, water absorption, minimum and maximum dry densities with a vibrating table, California Bearing Ratio (CBR) and Los Angeles (LA) abrasion tests. Shear strength properties of the recycled Foamed Glass were studied through large-scale direct shear tests. This recycled Foamed Glass is classified as a gap graded material. Due to high porosity, the coarse particles of this material have high water absorption of 60% and low particle density of 4.54 kN/m3, which is much lower than that of water. The minimum and maximum dry densities of this material are very low of 1.67 and 2.84 kN/m3, respectively. The LA abrasion of Foamed recycled Glass is lower than the requirement for pavement base/subbase material, being of 94%. The shear resistance at small shear displacement is thus low as shown by low CBR value of 9-12%. However, the shear resistance at large shear displacement is high as shown by high cohesion and friction angle of 23.36 kPa and 54.7°, respectively. The environmental assessment included pH value, organic content, total and leachate concentration of the material for a range of contaminant constituents. All the hazardous concentrations in the leachate are far lower than 100 times of those of the drinking water standards, indicating the Foamed recycled Glass as a non-hazardous material. The energy savings assessment demonstrates that the use of Foamed recycled Glass as engineering material has much lower energy consumption relative to a conventional aggregate-cement material in construction projects. The lightweight properties of the Foamed recycled Glass coupled with its satisfactory engineering and environmental results, particularly its high friction angle, indicates that the material is ideal for usage as a lightweight construction material in engineering applications such as non-structural fills in embankments, retaining wall backfill and pipe bedding.
Mert Eksi - One of the best experts on this subject based on the ideXlab platform.
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green roof substrates effect of recycled crushed porcelain and Foamed Glass on plant growth and water retention
Urban Forestry & Urban Greening, 2016Co-Authors: Mert Eksi, Bradley D RoweAbstract:Abstract A study was conducted in a controlled environment greenhouse to examine the potential of recycled crushed porcelain and Foamed Glass for use as a component of green roof substrates. Porcelain and Foamed Glass substrates were compared to heat-expanded shale which served as the control. Each finished substrate was analyzed per German FLL guidelines to determine granulometric distribution, bulk density, total porosity, water-holding capacity, saturated hydraulic conductivity, pH, soluble salts, organic matter content, and cation exchange capacity. Both substrates met FLL Guidelines except the porcelain substrate contained a greater percentage of larger particles and its maximum water holding capacity was lower than recommended. Two plant species were used in the study, Sedum album (stonecrop) and Ocinum x citriodolum (lemon basil). Data collected included substrate volumetric moisture content (VMC), plant growth, biomass accumulation, and plant stress as measured by chlorophyll fluorescence. Substrate VMC was generally greater in shale than in Foamed Glass or porcelain. At the end of the study plant growth index was greatest for stonecrop growing in shale, but there was no difference among the substrates for basil. However, plants of both basil and stonecrop accumulated the most total biomass when grown in shale. It is probable that water retention could be improved for both recycled crushed porcelain and Foamed Glass if more attention was paid to reducing particle size during processing. If so, then they may perform equal to heat expanded shale when incorporated into green roof substrates. In the case of porcelain, its use could divert some waste from landfills and greatly reduce the embodied energy required to construct a green roof.