## 2 Materials and Methods
### Mortars  
The first attempt to valorize the cork waste involved its use as filler within mortars. A commercially available mortar (GeoCalce Antisimico G by Kerakoll S.p.A., Sassuolo, MO, Italy) for historical buildings restoring and improving seismic resistance was considered. The binder is mainly composed of natural hydraulic lime NHL 3.5 and Portland cement. While the aggregate has a particle size between 0 mm and 2.5 mm, and a silicate-carbonate mineralogic composition. The technical data sheet points out an optimized effective water (w\({}_{\text{eff}}\))-to-mortar ratio of 0.204, and a fresh mortar flow diameter of 180 mm (UNI EN 459-2:2002). Moreover, it certifies the mortar as belonging to the M15 strength class (UNI EN 998-2). Increasing cork content was added from 1 wt% to 4 wt% of mortar, which in terms of volume corresponds to much higher percentages, 16 vol% and 65 vol%, respectively. The mix design of the four lime-based mortars containing cork waste is reported in Table 1 compared to the reference commercial one. As displayed in Table 1, a contribution of effective water (w\({}_{\text{eff}}\)) was set to reproduce an effective water-to-mortar ratio equal to 0.204. At the same time, extra water (w\({}_{\text{extra}}\)) was also considered to compensate for the amount of water absorbed by the cork, as assessed by the WA test on cork waste. The workability of the reference mortar (flow diameter of 180 mm) was set as the target value to be also maintained for mixes containing cork. Thereby, the flow table test (UNI EN 459-2:2002, performed through Flow Table 64, ControlsGroup, Milan, Italy) was preliminary involved to evaluate the effect of filler addition on workability. In order to improve the workability of the fresh mortars containing cork waste, a commercial superplasticizer was considered following its datasheet prescriptions and as reported in Table 1. Cork contents higher than 4 wt% were not considered due to workability issues. First, water and mortar were mixed at low speed (300 rpm) for 30 s through a high-speed laboratory mixer (RW20 DZM, IKA-Werke GmbH & Co. KG, Staufen, Germany), then the cork was added, continuing mixing for other 30 s. Subsequently, the mixing phase continued for 1:30 min at high speed (500 rpm), following the prescriptions of UNI EN 459-2:2002. The mixes were cast into 40 40 160 mm\({}^{3}\) and 300 300 30 mm\({}^{3}\) formworks to produce samples for the three-point bending and thermal conductivity tests, respectively. Four samples for mechanical tests and three for thermal conductivity were produced for each mortar type. According to UNI EN 196-1, samples were cured for 28 days in a climatic chamber with RH 90% 5% and temperature of 20 C 2 C. Moreover, additional 7 days of cure at laboratory conditions (RH 60% 5% and temperature of 25 C 2 C) were considered to have complete evaporation of the water potentially still present in cork particles. Four 40 40 160 mm\({}^{3}\) samples for each designed mix were mechanically tested through three-point bending, while a compressive strength test was carried out on four 40 40 40 mm\({}^{3}\) residual samples from the three-point bending test. The tests were performed following the UNI EN 196-1:2005 and using a universal testing machine (UTM, INSTRON 5567) equipped with a load cell of 30 kN. The three-point bending test was performed at a nominal rate of 1 mm/min under displacement control mode, and a distance  
\begin{table}
\begin{tabular}{c c c c c c c} \hline
**Cork** **(wt\%)** & **Cork** **(vol\%)** & **Cork** **(g)** & **Mortar 1** & **Effective Water 2** & **Extra** & **Superplast. ** \\
**(**w\%)** & **(vol\%)** & **(g)** & **(g)** & **(g)** & **Water 3 (g)** & **(g)** \\ \hline
0 & 0.00 & 0.00 & 8041.04 & 1604.40 & 0.00 & 0.00 \\
1 & 16.15 & 69.31 & 6931.04 & 1413.93 & 122.88 & 29.6 \\
3 & 48.49 & 162.04 & 5431.49 & 1108.02 & 288.88 & 49.84 \\
4 & 64.66 & 196.05 & 4901.29 & 999.86 & 347.58 & 44.96 of 10 cm was set between the two steel supports.