The Effects of Acrylate Impregnation of Black Spruce Timber as Connectors Strength

Abstract

Chemical impregnation of black spruce was conducted to enhance the wood embedment capacity. The formulation was made of 1,6 hexanediol diacrylate, trimethylpropane triacrylate, and a polyester acrylate oligomer. A second formulation, same as the first but with 1% wt of SiO2 nanoparticles, was selected to investigate the potential of nanoparticles and to improve the efficiency of the treatment. The wood embedment capacity was carried out by a dowel-bearing test, which was performed for the two treatments and for an untreated wood group. Both treatments showed an increase of strength of nearly 50% when compared to untreated samples. Micrograph views revealed that the impregnation solution penetrated into the wood only up to 100 μm. Hence, with low chemical consumption, the structural bearing capacity can be significantly increased.

Impact of a reinforcement treatment with acrylate impregnation on the mechanical behavior of black spruce as connector member

“…5, the slopes of lines for the stiffness are increasing with the enlargement of the diameter, due to the smaller bolt slenderness associated to brittle failure and higher stiffness. The lesser influence of treatment on stiffness than on bearing strength is due to the low penetration of formulation into the wood as seen in Lafond, Blanchet, Landry, Galimard and Ménard [21]. Fig.…”

“…Most of the time, high chemical retentions are wanted to distribute the solution equally and fully in the wood. Hence, previous studies [21] showed that impregnation of low permeable species, like black spruce, resulted in a noticeable increase in mechanical resistance without high chemical retention. Therefore, surface treatments with limited penetration, such as brushing and pulverisation, were tested in preliminary work.…”

“…As it showed the highest potential, this last method was retained for further experiments. The impact of the impregnation treatment with and without nanoparticles on the dowel bearing strength of black spruce was presented in the work of Lafond, Blanchet, Landry, Galimard and Ménard [21]. A better understanding of the strain behavior of wood after treatment was needed to explain the 50% strength increase.…”

Trends in Chemical Wood Surface Improvements and Modifications: A Review of the Last Five Years

“…Various impregnation agents were studied by Neyses et al to achieve the same goal, although the results were not as satisfying [235]. Lafond et al improved the embedment capacity of black spruce connectors through the impregnation of acrylates [236]. They found that a chemical retention of 7% could improve the bearing strength of the connector by 48% and their stiffness by 27%.…”

Performance evaluation of a wood treatment for connections with dowel-type bolts

“…The techniques for improving the dowel-type connection strength involve the study of friction between the contact surface of the fastener and wood, as well as the study of embedment performance through the improvement of the wood (Rodd and Leijten 2003). In order to study and improve the behavior of these connection types, several studies have been conducted (Gattesco 1998;Mungwa et al 1999;Sawata and Yasumura 2002;Pizzi et al 2006;Pantelides et al 2010;Franke and Magnière 2014b;Lafond et al 2016Lafond et al , 2017. Some research emphasized the improvement of mechanical performance of this type of connection through the wood modification using impregnation treatment (Lafond et al 2016(Lafond et al , 2017.…”