scholarly journals Performance Evaluation of Cementless Composites with Alkali-Sulfate Activator for Field Application

Materials ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 5410
Author(s):  
Jaehyun Lee ◽  
Taegyu Lee ◽  
Seungwoo Lee ◽  
Hyeonggil Choi
Keyword(s):  
Global Warming ◽  
Performance Evaluation ◽  
Global Warming Potential ◽  
Ordinary Portland Cement ◽  
Acid Resistance ◽  
Field Application ◽  
Hydration Products ◽  
Calcium Silicate Hydrates ◽  
The Matrix ◽  
Alkali Activated

This study analyzed the performance evaluation of alkali-activated composites (AAC) with an alkali-sulfate activator and determined the expected effects of applying AACs to actual sites. Results revealed that when the binder weight was increased by 100 kg/m3 at 7 days of age, the homogel strength of ordinary Portland cement (OPC) and AAC increased by 0.9 and 5.0 MPa, respectively. According to the analysis of the matrix microstructures at 7 days of age, calcium silicate hydrates (C–S–H, Ca1.5SiO3.5·H2O) and ettringite (Ca6Al2(SO4)3(OH)12·26H2O) were formed in AAC, which are similar hydration products as found in OPC. Furthermore, the acid resistance analysis showed that the mass change of AAC in HCl and H2SO4 solutions ranged from 36.1% to 88.0%, lower than that of OPC, indicating AAC’s superior acid resistance. Moreover, the OPC and AAC binder weight ranges satisfying the target geltime (20–50 s) were estimated as 180.1–471.1 kg/m3 and 261.2–469.9 kg/m3, respectively, and the global warming potential (GWP) according to binder weight range was 102.3–257.3 kg CO2 eq/m3 and 72.9–126.0 kg CO2 eq/m3. Therefore, by applying AAC to actual sites, GWP is expected to be 29.5 (28.8%)–131.3 (51.0%) kg CO2 eq/m3 less than that of OPC.

scholarly journals Acid Resistance of Lightweight Brick Powder Based Alkali Activated Material from Construction and Demolition Wastes

2018 ◽  
Author(s):  
Kai Tai Wan ◽  
Amende Sivanathan ◽  
Gediminas Kastiukas ◽  
Xiangming Zhou
Keyword(s):  
Acid Resistance ◽  
Strength Loss ◽  
Construction And Demolition Waste ◽  
Demolition Waste ◽  
Construction And Demolition Wastes ◽  
Brick Powder ◽  
Structural Applications ◽  
The Matrix ◽  
Similar Density ◽  
Alkali Activated

The annual construction and demolition waste (CDW) generated from EU construction sector was 850 million tons, which represented 31% of the total waste generation and about 28% of CDW was ceramics (bricks and tiles). In this study, the feasibility of using CDW brick powder as the precursor of alkali activated mortar (AAM) and extruded polystyrene (XPS) as the lightweight aggregates to form lightweight brick powder AAM (LW-BP-AAM) for non-structural applications was investigated. The thermal conductivity of LP-BPAAM was 0.112 W/m·K with density of about 1,135 kg/m3 which was lower than the counterparts with similar density in literature. The acid resistance of LW-BP-AAM is comparable to conventional fly ash based AAM and superior than ordinary Portland cement. From the scanning electron microscopy with energy dispersive X-ray spectroscopy, there was no severe damage on the surface of LW-BP-AAM but aluminate was removed from the matrix which was further verified in Fourier transform infrared spectroscopy. The mass and strength loss of LP-BP-AAM was 1.5% and 33%, respectively. Although the compressive strength of the LP-BP-AAM was low (about 1.8 MPa), it can be improved by optimising the particle size of the XPS aggregates.

scholarly journals Life Cycle Assessment of alkali activated materials: preliminary investigation for pavement applications

2021 ◽  
Vol 6 ◽  
pp. 124-130
Author(s):  
Francesca Lolli ◽  
Kimberly E. Kurtis
Keyword(s):  
Global Warming ◽  
Global Warming Potential ◽  
Capital Investment ◽  
Mechanical Performance ◽  
Preliminary Investigation ◽  
Raw Material ◽  
Cement Concrete ◽  
Usual Practice ◽  
The Impact ◽  
Alkali Activated

The capital investment in the US for construction and maintenance of the infrastructure road network is $150 billion/year. Investments in OECD countries will likely stabilize, while other countries will face an exponential growth of investments for infrastructures driven by the development of metropolitan cities. Continued “business-as-usual” practice for portland and asphalt cement concrete pavement construction ignores the increasing warning calls for the identification of more sustainable and less energy intensive paving materials. Alkali activated materials concrete (AAM) have been studied with growing interest during the last three decades. AAM show promising results in terms of mechanical performance, while also having a global warming potential impact 30-80% less than that of portland cement concrete. The global warming potential of AAM is closely dependent on the: 1) activating solution used to activate the raw material and 2) origin of the raw material. Specifically, the impact of the transport for both of these components is ~ 10% of its global warming potential. Hence, to increase the adoption of AAM for pavements, it is fundamental to analyze the existing literature to clarify the link between environmental impact and mechanical performance, identifying opportunities for applications that are tailored to the local availability of raw material.

scholarly journals Variation in Soil Properties Regulate Greenhouse Gas Fluxes and Global Warming Potential in Three Land Use Types on Tropical Peat

Atmosphere ◽  
2018 ◽  
Vol 9 (12) ◽  
pp. 465 ◽  
Author(s):  
Kiwamu Ishikura ◽  
Untung Darung ◽  
Takashi Inoue ◽  
Ryusuke Hatano
Keyword(s):  
Global Warming ◽  
Soil Moisture ◽  
Groundwater Level ◽  
Global Warming Potential ◽  
C:N Ratio ◽  
Co2 Flux ◽  
Nitrate Content ◽  
N2o Flux ◽  
Ch4 Flux ◽  
In The Beginning

This study investigated spatial factors controlling CO2, CH4, and N2O fluxes and compared global warming potential (GWP) among undrained forest (UDF), drained forest (DF), and drained burned land (DBL) on tropical peatland in Central Kalimantan, Indonesia. Sampling was performed once within two weeks in the beginning of dry season. CO2 flux was significantly promoted by lowering soil moisture and pH. The result suggests that oxidative peat decomposition was enhanced in drier position, and the decomposition acidify the peat soils. CH4 flux was significantly promoted by a rise in groundwater level, suggesting that methanogenesis was enhanced under anaerobic condition. N2O flux was promoted by increasing soil nitrate content in DF, suggesting that denitrification was promoted by substrate availability. On the other hand, N2O flux was promoted by lower soil C:N ratio and higher soil pH in DBL and UDF. CO2 flux was the highest in DF (241 mg C m−2 h−1) and was the lowest in DBL (94 mg C m−2 h−1), whereas CH4 flux was the highest in DBL (0.91 mg C m−2 h−1) and was the lowest in DF (0.01 mg C m−2 h−1), respectively. N2O flux was not significantly different among land uses. CO2 flux relatively contributed to 91–100% of GWP. In conclusion, it is necessary to decrease CO2 flux to mitigate GWP through a rise in groundwater level and soil moisture in the region.

scholarly journals Influence of technical and electrical equipment in life cycle assessments of buildings: case of a laboratory and research building

2021 ◽  
Author(s):  
E. Hoxha ◽  
D. Maierhofer ◽  
M.R.M Saade ◽  
A. Passer
Keyword(s):  
Global Warming ◽  
Environmental Impacts ◽  
Global Warming Potential ◽  
Electrical Equipment ◽  
Primary Energy ◽  
Electronic Equipment ◽  
Detailed Result ◽  
Detailed Calculation ◽  
System Boundary ◽  
Operational Energy

Abstract Purpose A detailed assessment of the environmental impacts of the building requires a substantial amount of data that is time- and effort-consuming. However, limitation of the system boundary to certain materials and components can provide misleading impact calculation. In order to calculate the error gap between detailed and simplified assessments, the purpose of this article is to present a detailed calculation of the environmental impacts of the building by including in the system boundary, the technical, and electrical equipment. Method To that end, the environmental impacts of a laboratory and research building situated in Graz-Austria are assessed following the EN-15978 norm. Within the system boundaries of the study, the material and components of building fabric, technical, and electronic equipment for the building lifecycle stages of production, construction, replacement, operational energy and water, and end-of-life are considered. The input data regarding the quantity of materials is collected from the design and tendering documents, invoices, and from discussion with the head of the building’s construction site. Primary energy and global warming potential indicators are calculated on the basis of a functional unit of 1 m2 of energy reference area (ERA) per year, considering a reference building service life of 50 years. Results and discussion The primary energy indicator of the building is equal to 1698 MJ/m2ERA/year. The embodied impacts are found to be responsible for 28% of which 6.4% is due to technical and electronic equipment. Furthermore, the embodied impacts for the global warming potential, equal to 28.3 kg CO2e/m2ERA/year, are responsible for 73%. Together, technical and electrical equipment are the largest responsible aspects, accounting for 38% of the total impacts. Simplified and detailed result comparisons show a gap of 29% and 7.7% for global warming and primary energy indicators. These differences were from the embodied impacts and largely from the exclusion of electrical equipment from the study’s system boundary. Conclusions Technical and electrical equipment present a significant contribution to the overall environmental impacts of the building. Worthy of inclusion in the system boundary of the study, the environmental impacts of technical and electrical equipment must be calculated in detail or considered with a reliable ratio in the early design phase of the project. Further research is necessary to address the detailed impact calculation of the equipment and notably the minimization of their impacts.

scholarly journals Environmental impacts of wooden, plastic, and wood-polymer composite pallet: a life cycle assessment approach

2021 ◽  
Author(s):  
Md.Musharof Hussain Khan ◽  
Ivan Deviatkin ◽  
Jouni Havukainen ◽  
Mika Horttanainen
Keyword(s):  
Sensitivity Analysis ◽  
Global Warming ◽  
Life Cycle Assessment ◽  
Life Cycle ◽  
Polymer Composite ◽  
Global Warming Potential ◽  
Consequential Life Cycle Assessment ◽  
Wood Polymer ◽  
Biogenic Carbon ◽  
Wood Polymer Composite

Abstract Purpose Waste recycling is one of the essential tools for the European Union’s transition towards a circular economy. One of the possibilities for recycling wood and plastic waste is to utilise it to produce composite product. This study analyses the environmental impacts of producing composite pallets made of wood and plastic waste from construction and demolition activities in Finland. It also compares these impacts with conventional wooden and plastic pallets made of virgin materials. Methods Two different life cycle assessment methods were used: attributional life cycle assessment and consequential life cycle assessment. In both of the life cycle assessment studies, 1000 trips were considered as the functional unit. Furthermore, end-of-life allocation formula such as 0:100 with a credit system had been used in this study. This study also used sensitivity analysis and normalisation calculation to determine the best performing pallet. Result and discussion In the attributional cradle-to-grave life cycle assessment, wood-polymer composite pallets had the lowest environmental impact in abiotic depletion potential (fossil), acidification potential, eutrophication potential, global warming potential (including biogenic carbon), global warming potential (including biogenic carbon) with indirect land-use change, and ozone depletion potential. In contrast, wooden pallets showed the lowest impact on global warming potential (excluding biogenic carbon). In the consequential life cycle assessment, wood-polymer composite pallets showed the best environmental impact in all impact categories. In both attributional and consequential life cycle assessments, plastic pallet had the maximum impact. The sensitivity analysis and normalisation calculation showed that wood-polymer composite pallets can be a better choice over plastic and wooden pallet. Conclusions The overall results of the pallets depends on the methodological approach of the LCA. However, it can be concluded that the wood-polymer composite pallet can be a better choice over the plastic pallet and, in most cases, over the wooden pallet. This study will be of use to the pallet industry and relevant stakeholders.

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