ISSN: 1945-7553
Page Count: 11

Effect of Pyrolytic Temperatures on the Longitudinal Strength of Dry Douglas-Fir

Schaffer, EL
Research engineer, Forest Products Laboratory, USDA,

Abstract

Compressive and tensile strength of dry Douglas-fir was measured through rapid constant deformation rate tests at temperatures from 25 to 288°C, at initial thermoequilibrium and after 2 h of heating.

The tensile strength decreased slowly with increasing temperatures to 175°C. Above 175°C, the tensile strength reduces rapidly. This is attributed to alteration of the cellulosic fraction of wood.

The compressive strength decreases more uniformly with temperatures increasing to 288°C due to changes occurring in all three basic wood components with change in temperature.

A first-order reaction equation for bond rupture/formation was adopted to describe the response. Including only terms for bond rupture resulted in good correlation to the observed strength response at reaching thermoequilibrium.

Keywords:
fire performance, wood, temperature, fracture mechanics, thermal degradation, strength, pyrolysis, durability

Paper ID: JTE10025J
DOI: 10.1520/JTE10025J
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