*2.1. Material*

The primary binder used was Portland cement type 10 (GU, General Use), an ordinary CSA (Canadian Standards Association).

The SP selected for this research project was provided by Polycore Inc, Quebec, Canada.

The wood-cement mixtures were prepared with air-dried wood particles obtained from white spruce (*Picea glauca*) trees harvested at the Petawawa Research Forest in Mattawa (ON), Canada. The wood chips were refined with a Pallmann PSKM8-400 ring refiner (Ludwig Pallmann K.G, Zweibrücken, Germany). Then, the wood particles were screened using nine sieve sizes: 1.19, 1.40, 1.70, 2.38, 2.80, 3.35, 4.00, 4.46 and 5.00 mm.

The regular GB used in the study for comparison purposes were 12.7 mm [1/2 in] in thickness. They are commercialized by Georgia Pacific under the trade name ToughRock®. They were typical regular drywall boards used for interior partitioning in building construction.

### *2.2. Material Characterisation*

#### 2.2.1. Wood Particles

Figure 1 shows the wood particles size distribution by mass. According to the results, all of the particles are smaller than 5 mm in size and the highest volume fraction (37%) is the particles with a diameter of 1.7 mm. In the study of Vu et al. [11], the size of the wood particles was less than 3 mm and the highest volume fraction was 1.7 mm. Wood particles size reaches a maximum of 5 mm for the purpose of increasing the mechanical strength of the particleboard.

**Figure 1.** Wood particles size distribution.

#### 2.2.2. Steatite Powder

#### Chemical Composition

Table 1 shows the results of the chemical analysis of SP. The combined content of aluminum oxide (Al2O3 = 0.7%), iron oxide (Fe2O3 = 6.32%), and silicon dioxide (SiO2 = 38.3%) reaches 45.32%, while the minimum value required for the material to qualify as a pozzolan is 70%. The relative mass loss during combustion observed at 950 ◦C was 20.4%, which is considerably more than the maximum requirement for pozzolans set at 12%. The alkali content recorded (%Na2O + 0.658 × %K2O) was less than 0.23%, which is lower than the maximum alkali content of 1.5% required for pozzolans [18]. Therefore, SP does not qualify as a pozzolan. The specific gravity of SP was found to be 2.91. This is lower than the specific gravity of Portland cement (3.15), but larger than for mineral aggregates typically used in cementitious materials (limestone, granite, quartzite).

**Table 1.** Composition and properties of steatite powder.

