A review on Life Cycle Assessment, Life Cycle Energy Assessment and Life Cycle Carbon Emissions Assessment on buildings

https://www.repository.cam.ac.uk/bitstream/1810/247518/1/Sharma%20et%20al%202015%20Elsevier.pdf

Engineered bamboo for structural applications

Novel engineered wood and bamboo composites for structural applications: State-of-art of manufacturing technology and mechanical performance evaluation

Engineered mycelium composite construction materials from fungal biorefineries: A critical review

When wood is exposed to elevated temperatures, changes can occur in its chemical structure that affect its performance. The extent of the changes depends on the temperature level and the length of time under exposure conditions. The changes in chemical structure may be manifested only as reduced strength, and hydroscopic water and volatile oil weight loss. In contrast, very drastic chemical changes may result in reduced strength and significant carbohydrate weight loss. At temperatures below 100°C, permanent reductions in strength can occur. The magnitude of the reduction depends on the moisture content, heating medium, exposure period and species. The strength degradation is usually not considered to result from the same thermal decomposition of the wood that occurs above 100°C, since no significant carbohydrate weight loss occurs. The strength degradation is probably due to depolymerization reactions, although little research has been done on the chemical mechanism. Reviews by Gerhards (1979, 1982, 1983) and Koch (1985) summarize reduction in strength at temperatures below 100oC (See Strength). If the wood has been treated with a chemical to reduce its flammability, more significant reductions in strength can occur at lower temperatures than for untreated wood. This is due to the presence of chemicals that catalyze the dehydration and depolymerization reactions. A review by Winandy (1987) summarizes the effects of elevated temperatures on strength properties of treated wood. At temperatures above 100oC, chemical bonds begin to break. The rate at which the bonds are broken increases as the temperature increases. Between 100°C and 200oC, noncombustible products, such as carbon dioxide, traces of organic compounds and water vapor, are produced. Above 200oC the celluloses break down, producing tars and flammable volatiles that can diffuse into the surrounding environment. If the volatile compounds are mixed with air and heated to the ignition temperature, combustion reactions occur. The energy from these exothermic reactions radiates to the solid material, thereby propagating the combustion, or pyrolysis, reactions. If the burning mixture accumulates enough energy to emit radiation in the visible spectrum, the phenomenon is known as flaming combustion (see Fire and Wood). Above 450oC all volatile material is gone. The residue that remains is an activated char that can be oxidized to carbon dioxide, carbon monoxide and water vapor. Oxidation of the char is referred to as afterglow. The thermal degradation of wood can be represented by two pathways (Fig. 1), one occurring at high temperatures (>300oC), the other at lower temperatures. These two competing reactions occur simultaneously. Fire retardants work by shifting degradation to the low-temperature pathway.

태양선택 흡수면의 Thermal Degradation

This paper presents a study aimed to characterize the structural performance of laminated bamboo lumber (LBL) and bamboo glulam beams (BGBs) as a first step to evaluate their potential application as a structural material. LBL was tested to determine their flexural, tensile, and shear properties, whereas BGBs were tested for their flexural, shear, and compressive properties. The BGBs were fabricated using two different adhesives: isocyanate resin (ISO) and phenol-resorcinol formaldehyde (PRF). BGBs with ISO performed better in bending strength, whereas the stiffness of glulams with both glue types was equivalent. Irrespective of the glue type, failure modes and shear test data showed BGB bending strength was limited by interlaminar shear in the LBL used in BGB fabrication. From the experimental study, it is concluded that the LBL does possess higher allowable and average strength values in tension and bending and comparable stiffness values, with much less variability to a commonly used structural species of wood, Douglas fir. The potential of using LBL in framing applications exists. However, certain impediments need to be addressed and researched before acceptance of LBL and BGB in the construction marketplace.

Structural Performance of Glued Laminated Bamboo Beams

This is the publisher’s final pdf. The published article is copyrighted by Faculty of Forestry, Zagreb University and can be found at: http://hrcak.srce.hr/drvnaindustrija.

/pdf/sustainable-development-and-green-buildings-2jwefti4f7.pdf

Sustainable Development and Green Buildings

Background: The University of Talca (UT), since 2012, has been annually tracking the carbon footprint (CF) based on the Greenhouse Gas (GHG) Protocol for all its five campuses. The purpose of this paper is to illustrate the trajectory for determining the CF on campuses and identify the stressors. Methods: GHG protocol separates emissions into three scopes—1) direct; 2) indirect; 3) other indirect emissions. This study reports the emissions on the Talca campuses that are related to Scopes 1 through 3. The data is closely studied to draw inferences on the factors most affecting CF and recommend improvements. Results: The estimation of the CF in Scope 1 and Scope 2 were 2 0.03 tCO2e and 0.25 tCO2e per person per year, respectively. Results show Scope 3, which measures indirect emissions generated by activities like transportation of people, produced the highest contribution of 0.41 tCO2e per person to the UT’s CF in 2016. Conclusions: The study strongly suggested that transportation of students and faculty to and from the campus is one of the main stressors. The study of the main campus of Talca to quantify the CF is of immense value to institutions of higher educations as it provides a guideline and a comparative metric for other institutions.

https://www.mdpi.com/2071-1050/12/1/181/pdf

Carbon Footprint Estimation in a University Campus: Evaluation and Insights

The development of cross-laminated timber (CLT) technology has opened up new opportunities for low-density hardwood species, which have traditionally not been rated as construction-grade materials for structural engineering applications. Several characteristics of CLT, namely thermal performance, seismic behavior, and speed of construction, have raised interest among designers. The CLT technology has recently been used for residential and nonresidential multistory buildings and it has been identified as one of the ways of achieving tall timber building construction. As CLT gains acceptance in the industry, low-density wood species, not specified in current ANSI standards, need to be investigated for potentially successful use in CLT panels. This paper presents a study that demonstrates the viability of a Forest Stewardship Council (FSC) certified sustainable plantation grown low-density species, hybrid poplar (marketed as Pacific Albus), for use in performance-rated CLT panels by following the ANS...

/pdf/viability-of-hybrid-poplar-in-ansi-approved-cross-laminated-18bgts30cg.pdf

Viability of Hybrid Poplar in ANSI Approved Cross-Laminated Timber Applications

The construction industry has relied heavily on wood and wood-based composites, such as oriented strand board (OSB) and plywood for timber frame construction. Therefore, it is highly imperative to categorize the response of wood-based composites when exposed to elevated temperatures for a sustained period of time. The essence of fire-resistant structural design is to ensure that structural integrity be maintained during and after the fire, prevent collapse and maintain means of egress. Another aspect is to assess post-fire structural integrity and residual strength of existing structure. The objective of this project was (a) to study the effect of exposure time on bending strength (MOR) of OSB and plywood at elevated temperatures, (b) to interpret any relationships between different temperature and time of exposure using a kinetics model for thermal degradation of strength, and (c) to develop a master curve representing temporal behavior of OSB and plywood at a reference temperature. As much as 1,152 samples were tested in static bending as a function of exposure time and several temperatures. Strength (MOR) of both OSB and plywood decreased as a function of temperature and exposure time. These results were fit to a simple kinetics model, based on the assumption of degradation kinetics following an Arrhenius activation energy model. The apparent activation energies for thermal degradation of strength were 54.1 kJ/mol for OSB and 62.8 kJ/mol for plywood. Furthermore, using the kinetics analysis along with time–temperature superposition, a master curve was generated at a reference temperature of 150°C which predicts degradation of strength with time on exposure at that reference temperature. The master curves show that although plywood has a higher initial strength, OSB performs better in terms of strength degradation after exposure to elevated temperature.

/pdf/thermal-degradation-of-bending-strength-of-plywood-and-dvjbmupmyb.pdf

Arijit Sinha

Papers

Structural Performance of Glued Laminated Bamboo Beams

Sustainable Development and Green Buildings

Carbon Footprint Estimation in a University Campus: Evaluation and Insights

Viability of Hybrid Poplar in ANSI Approved Cross-Laminated Timber Applications

Thermal degradation of bending strength of plywood and oriented strand board: a kinetics approach