Glulam and laminated veneer lumber protected by a combination of treatment with borate by two processes, and a film-forming coating, were exposed outdoors in an above-ground field test using a modified post and rail test design. After eight years’ exposure, early to moderate decay was found in untreated test units, while those which were borate-treated by either method were generally sound up to six years and showed greatly reduced decay at eight years.
Glulam manufactured from laminating stock of three species pre-treated with ACQ-D or CA was exposed outdoors in an above-ground field test using a modified post and rail test design. After six years’ exposure, early to moderate decay was found in untreated test units, while those which were preservative-treated were completely sound.
Field tests of untreated and preservative-treated glulam beams in outdoor exposure, in ground contact and above ground, were inspected for decay after five years. Copper azole and ACQ-D-treated material was in excellent condition, while moderate to severe decay was present in untreated non-durable material. Early stages of decay were also noted in yellow cedar glulam in the above-ground test. Using galvanized rather than stainless steel fasteners appeared to have a protective effect against decay in untreated material, supporting the hypothesis that zinc from the sacrificial coating on galvanized bolts inhibits germination of basidiospores.
The objective of this study was to examine new attributes and conduct economic analyses for composite CLT (CCLT) and value-added appearance-based CLT products manufactured with varying substitution of softwood lumber with structural composite lumber (SCL) and hardwood lumber. Incentives for including such materials could be aesthetic, structural and economic.
Structural and aesthetic property assessments were carried out on prototype CLT panels. Multiple CLT panel configurations (17) were evaluated to assess the effects of including hardwood and SCL materials in the layups. Presence of hardwood in the panels’ configuration generally led to higher checking and density. Because of the higher shrinkage of hardwood, the bondline suffered from more delamination. A lower density hardwood (aspen) was included in some configurations and exhibited a greater direct compatibility with current Canadian manufacturing process. Changes to this process, such as selecting a hardwood specific adhesive may lead to improvements.
SCL’s inclusion in the panels’ layup revealed to be fairly compatible with the current CLT manufacturing process. Both LVL and LSL products performed equally well or better than the reference lumber-made CLT panel for the bondline quality, dimensional stability and visual defects development. The efficiency of the manufacturing process of the prototype CLT panels was improved when EWP was included in the layup. The lesser amount of components and the readily flat surface of SCL may have a positive impact on the economics of CLT manufacturing due to an improved efficiency.
Substitution products evaluated are characterized by a higher market price than lumber. CLT made from a combination of LSL or LVL and softwood lumber would cost about $100/m3 more to get the same return if there were no changes in the manufacturing. The burden of this cost increase would have to be offset by unique series of attributes that would add value for the customer and/or by a greater manufacturing efficiency.
The relationship between proof load level of fingerjoined lumber and degree of cure of adhesive bonds was investigated. Tension tests were completed for two different degrees of cure for two different adhesives. The proof load level determined for the partially cured joints did not cause damage to the joints that survived the proof test.
Preliminary guidelines for determining appropriate proof load levels for testing fingerjoined lumber with partially cured joints were proposed. The proposed guidelines will need to be validated through mill trials to demonstrate their efficacy and reliability to the manufacturer and third party inspection agency.
Keywords: fingerjoined lumber; tension proof testing/loading; partially cured adhesive bonds.
Proceedings of a Seminar organized by Forintek Canada Corp. and held in 1984. Increasing product yield and value of solid wood fiber is a common denominator in the forest products industries of Canada and all lumber producing countries around the world. As the quality of the existing forest resources decrease, the forest products wood working and building industries can expect a reduction in grade and length of lumber. One possible solution to this problem is to finger joint short materials into premium lengths, and produce higher value products. Finger jointing is an established process for the manufacture of glued-laminated lumber beams and wood mouldings. More recently, finger jointing has found applications in the production of structural lumber for building purposes. The seminar focused on: production systems, quality control, adhesives, economics, use of finger jointed products, regulations, marketing and government programs.