Experimental investigation on duration of load effect of novel inorganic-bonded bamboo composite under flexural load

Abstract

Conventional engineered wood and bamboo materials commonly require organic adhesives for adequate bonding. As an alternative solution in bio-based composites, a novel bamboo-based composite prepared with a magnesium-based inorganic adhesive was proposed herein, which is named as “inorganic-bonded bamboo composite” and abbreviated as InorgBam. This study investigates the duration of load (DOL) effect on InorgBam beams under long-term flexural load. The percentile matching method was used to obtain the short-term strengths matched to the long-term specimens, and the strength reduction of the long-term specimens was obtained. The DOL result were calibrated using the DOL empirical formulas and DOL damage models, including Gerhards, Foschi and Yao, and Nielsen models. The impact of the selected cumulative probability functions of short-term strength on the DOL analysis has also been discussed. Results illustrated that the strength reduction in the InorgBam was less than the prediction of Madison curve. The value of DOL coefficient determined with Foschi and Yao model was closest to that derived from the empirical fitted formula. The DOL effect of the InorgBam beams was significantly smaller than that of conventional engineered wood beams, which is beneficial for determining the design strength value of InorgBam material.