# Thermal Conductivity and Thermal Behavior of Mortar Containing Wood Shavings and Sawdust
## 2 Materials and Methods
This means that in the case of sawdust the same replacement percentage corresponds to a much larger amount of wood which results to a great loss of workability. This is attributed to the fact that wood shavings and wood sawdust absorbs more water compared to conventional aggregates [9]. So, the percentages for sawdust were kept low, 10 and 20%. The constituents were mixed in a mixer at a slow speed to obtain good homogenization. First, cement and aggregates mixing took place. Then, the water with superplasticizer diluted in it was added. Density of fresh concrete (\(D\)) was determined by measuring the mass of mortar (\(m_{u}\)) contained in a known volume (\(V_{u}\)) of a sample of fresh mortar as described in ASTM C138 [25]:  
\[D=\frac{m_{u}}{V_{u}} \tag{1}\]  
Specimens from each mixture were cast with dimensions 200 \(\times\) 200 \(\times\) 80 mm to perform thermal conductivity determination tests. After 48 h, the specimens were demoulded and then they were immersed in water until the age of 28 days. The curing temperature was about 20 \({}^{\circ}\)C. Then, specimens were left in ambient laboratory air (50% RH, 17 \({}^{\circ}\)C) for a month, until the determination of the thermal conductivity coefficient. The thermal con \begin{table}
\begin{tabular}{c c c c c c c} \hline  & **Replacement of** & **Wood** & **Cement** & **Fine** & **Water (kg)** & **Superplasticizer** \\  & **Aggregates (\%)** & **(kg)** & **(kg)** & **Aggregates (kg)** & **Water (kg)** & **(kg)** \\ \hline Ref-Sh & 0 & 0 & 300 & 1500 & 180 & 4.5 \\ B30 Sh & 30 & 17.6 & 300 & 1050 & 180 & 4.5 \\ B50 Sh & 50 & 29.3 & 300 & 750 & 180 & 4.5 \\ B70 Sh & 70 & 41 & 300 & 450 & 180 & 4.5 \\ Ref-Sd & 0 & 0 & 500 & 1500 & 300 & 5 \\ B10 Sd & 10 & 25.7 & 500 & 1350 & 300 & 5 \\ B20 Sd & 20 & 51.4 & 500 & 1200 & 300 & 5 \\ \hline \end{tabular}
\end{table} 
Table 1: Mix proportions. ductivity coefficient was determined by means of the guarded hot plate method according to European Standard EN 12667:2001. The equipment used was the TLP-300 of TAURUS Instruments (Fridingen an der Donau, Germany) (Figure 3). From the same mixes, also specimens with dimensions 40 \(\times\) 40 \(\times\) 160 mm were cast to study their thermal behavior under 100, 200, 300, 400, 500 and 600 \({}^{\circ}\)C. After 48 h, the specimens were demoulded and then they were immersed in water until the age of 28 days. The curing temperature was about 20 \({}^{\circ}\)C. Then specimens were left in ambient laboratory air for another 28 days to balance (50% RH, 17 \({}^{\circ}\)C). Then, they were subjected to temperatures in an oven for 15, 30 and 60 min. The specimens were left in the oven to gradually cool down, to avoid any thermal shock. After thermal strain, a non-destructive test of ultrasonic pulse velocity was carried out by using the method described in ASTM C 597 [26], specifically using a Portable Ultrasonic Non-Destructive Digital Indicating Tester (PUNDIT). Then, the flexural strength test was carried out by center-point loading as described in ASTM C 293 [27] on three specimens. The end parts of the prisms that were left intact after failure in flexure were used to carry out compressive strength tests by applying the load through square steel plates, 40 mm in size, at a uniaxial compressive test apparatus (CONTROLS-GROUP-Automax Multitest Control Console-Automatic Compression Tester 2.000 kN).