Treesearch

Buildings consume large amounts of materials and energy, making them one of the highest environmental impactors. Quantifying the impact of building materials can be critical to developing an effective greenhouse gas mitigation strategy. Using Athena Impact Estimator for Buildings (IE4B), this paper compares cradle-to-grave life-cycle assessment (LCA) results for a 12-story building constructed from cross-laminated timber (CLT) and a functionally equivalent reinforced concrete (RC) building. Following EN 15978 framework, environmental impacts for stages A1–A5 (product to construction), B2,...

Wood-plastic composites (WPC) contain wood fiber (or flour), thermoplastics and additives and are exposed to UV light, moisture, and biological deterioration in outdoor installations. Accelerated laboratory tests can help to predict the durability of WPCs, but long term evaluations are needed to validate these results. Field exposed above-ground WPC deck boards (30.5 x 139.7 x 609.6 mm) and in-ground (19 x 19 x 457 mm) stakes were visually evaluated near Saucier, Mississippi and Madison, Wisconsin over 17 years. Four blends were extruded on commercial-scale equipment containing additives...

It is well known that chemical modifications to improve decay resistance also reduce the equilibrium moisture content (EMC) of wood. The mechanism of this action, however, has been the subject of much debate. Several groups have suggested that decay resistance is a result of lower diffusion rates of fungal degradation agents through the wood cell wall. A recent paper explained the fundamental principles governing diffusion through the wood cell wall. This current paper summarizes the findings in that paper with respect to decay resistance of modified wood. In short, large scale motions of...

The favorable mechanical properties and performance of TEMPO-oxidized cellulose nanofibril (TOCNF) films has been limited by their brittleness and the incapability of obtaining thick enough materials for self-supported applications. In this study, lamination with room temperature curable epoxy was used to combat brittleness, increase thickness, and produce a more damage tolerant material. The effect of the volume fraction and layer thickness of both phases (e.g., TOCNF, epoxy), the number of layers, and the overall total thickness of the laminate, on the tensile and flexural properties are...

Laboratory-derived composition and pyrolysis data are essential inputs for the modeling of fire behavior. Recently, fire research has focused on live fuels including living wood and leaves, which exhibit sharp differences in moisture levels and chemical composition as compared to dead fuels. These leaf components have fuel properties that function in the spread of wildfire and must be considered in order to produce nuanced predictive models that reflect real life conditions. The goal of this study was to assemble a suite of methods that would achieve summative mass closure for analysis of...

The use of timber–concrete composite (TCC) bridges in the United States dates back to approximately 1924 when the first bridge was constructed. Since then a large number of bridges have been built, of which more than 1,400 remain in service. The oldest bridges still in service are now more than 84 years old and predominately consist of two different TCC systems. The first system is a slab-type system that includes a longitudinal nail-laminated deck composite with a concrete deck top layer. The second system is a stringer system that includes either sawn timber or glulam stringers supporting...

An approach for implementing statistical process control and other statistical methods as a cost-savings measure in the treated-wood industries is outlined. The purpose of the study is to use industry data to improve understanding of the application of continuous improvement methods. Variation in wood treatment is a cost when higher-than-necessary chemical retention targets are required to meet specifications. The data for this study were obtained in confidence from the American Lumber Standard Committee and were paired, normalized assay retentions for charges inspected by both the...

In February, total starts, permits, completions, new sales, and residential spending declined on a month-over-month basis. The silver lining—permits were the greatest since March 2007. On a year-over-year basis, most of the data indicated robust improvement, except for the decline in multifamily permits and total completions. Single-family under construction also decreased. New single-family house sales decreased, but on a yearly basis they were much greater than in 2019. Existing sales also improved. Single-family construction expenditures improved on a monthly and yearly basis.

The properties of cured wood adhesives are difficult to study because of the loss of water and other components to the wood, the influence of wood on the adhesive cure, and the effect of adhesive penetration on the wood interphase; thus, normal testing of a neat adhesive film is generally not useful. Most tests of wood adhesive bond strength are slow, laborious, can be strongly influenced by the wood and do not provide information on the kinetics of cure. Test method ASTM D 7998-19, however, can be used for fast evaluation of the strength of wood bonds. The use of a smooth, uniform, and...

For mills making paper with recovered fiber, removal of hydrophobic contaminants is essential for trouble-free operation of paper machines. Significant cost savings on paper machine operation can be achieved by reducing deposits, which results in better quality, reduced downtime, increased fiber yield, and reduced energy consumption.Bubble nucleation separation (BNS) is a relatively new process for removing hydrophobic particles. When vacu-um is applied to a slurry, dissolved gas bubbles nucleate on hydrophobic particles and drag them to the surface for easy removal. We constructed a 16-L...