Withdrawal resistance and lateral shear strength of the nail connector in cypress wood (Cupressus arizonica ) treated with ACC and ACQ with emphasis on the use in NLT

Nail laminated timber (NLT) is one of the engineered wood products which is widely used in construction. Due to the structure of NLT, it has a high tendency to absorb moisture and its moisture loss rate also is very low. Therefore, it is necessary to protect it against humidity and degradation agents. In this study, the effect of ACC and ACQ preservatives on the performance of withdrawal resistance and lateral strength of the nail fastener in cypress wood with emphasis on the use in NLT was investigated. To treat the layers, preservative solutions with a concentration of 2% were used to achieve the minimum retention required for use with ground contact according to AWPA requirements. Withdrawal resistance and lateral strength of nail were compared with NDS standard and yield limit formulas, respectively. Results showed that ACC and ACQ preservatives had no adverse effects on the mechanical resistance tested in this study, and thus there is no restriction to use the treated wood for manufacturing NLT. Also, the results showed that there is a good agreement between the resistance predicted by the equations presented in NDS and the experimental results. IIIs failure mode was observed in the treated and control samples.