## 2 Materials and Methods
### Methods  
Chemical analyses of pure metakaolin, AGWs and AGW-G composites were performed using a Spectro IQ X-ray fluorescence (XRF) analyzer (SPECTRO Analytical Instruments GmbH., Kleve, Germany), which allows the analysis of major and trace elements of solid, powder and liquid materials. This instrument has a target made of palladium; the target angle was 90\({}^{\circ}\) from the central beam, and the focal size was 1 mm \(\times\) 1 mm. The measurements were carried out in an inert helium atmosphere. The data obtained were evaluated using the computer program XLabPro, which enables automatic recalculation of the elemental content in the sample to the oxide form. The tested specimens were produced by the pressed-pellet method: 4.0 g of the material (particle size: 15-20 \(\upmu\)m) were mixed for 10 min with 0.9 g of the binder (HWC Hoechst wax, FLUXANA(r) GmbH & Co., KG, Bedburg-Hau, Germany). The compaction pressure was 80 kN. The samples were analyzed by X-ray diffraction (XRD) on a Bruker D8 Advance powder X-ray diffractometer in a Bragg-Brentano geometry using a Lynx Eye XE detector and CuK\(\alpha\) radiation (Bruker AXS, Karlsruhe, Germany). The powder sample was mounted on a planar substrate (diffraction-free silicon). Diffraction was recorded in the angular range of 4-80\({}^{\circ}\) 2\(\Theta\) with a step of 0.015\({}^{\circ}\) and a readout time of 0.8 s per step. The acquired X-ray diffraction patterns were qualitatively evaluated in the Diffrac.Eva 4.1. software (Bruker AXS, Karlsruhe, Germany, 2015) using the ICDD PDF-2 database (ICDD 2018). The organic substances in the AGW and subsequently in the AGW-G composites were determined on gas chromatography/mass spectrometry (GC/MS) equipment, consisting of a Trace 1310 gas chromatograph coupled with an ISQ single quadrupole system (ThermoScientific, Waltham, MA, USA) equipped with a CP5 capillary column (30 m \(\times\) 0.25 mm \(\times\) 25 \(\upmu\)m). Data were acquired and integrated using the Chromeleon system (ThermoScientific, Waltham, MA, USA). Dichloromethane and methanol (HPLC grade) were purchased from Sigma-Aldrich (St. Luis, MO, USA), and ethylene glycol from Penta (Prague, Czech Republic). The ground samples (\(<\)0.2 mm) were extracted with a mixture of dichloromethane and methanol (93:7, \(v/v\)) using an accelerated solvent extractor (ASE 150, Dionex, Sunnyvale, CA, USA). The extracts were filtered through a glass-fiber filter and concentrated using a Christ RVC 2-18 rotator evaporator. The total extracts were re-dissolved in 1.0 mL of dichloromethane/methanol (97:3) and analyzed. GC/MS analysis was performed using helium as the carrier gas with a constant flow rate of 1.5 mL/min. The extract solution (1 \(\upmu\)L) was injected into the GC system in splitless mode for each analysis. The injection port and detector temperatures were set at 250 \({}^{\circ}\)C; the oven temperature program started at 40 \({}^{\circ}\)C and was maintained for 1 min, after which it increased to 120 \({}^{\circ}\)C at 15 \({}^{\circ}\)C/min, then to 250 \({}^{\circ}\)C at 6 \({}^{\circ}\)C/min and finally to 300 \({}^{\circ}\)C at 12 \({}^{\circ}\)C/min, being maintained for 5 min. The analyte detected was identified by comparing the spectrum with the NIST mass spectral library and data from the literature. Each sample was analyzed three times, and the mean and the relative standard deviation (RSD) were calculated. The compound identified was quantified using ethylene glycol as a standard after its derivatization with bis(trimethylsilyl)trifluoroacetamide (BSTFA) in pyridine. Ethylene-glycol stock solutions were prepared in dichloromethane to achieve the five concentration levels of the calibrators: 1, 5, 10, 25 and 100 \(\upmu\)g/mL. The derivatization reagent (BSTFA, 25 \(\upmu\)L) and the catalytic reagent (pyridine, 25 \(\upmu\)L) were added to an aliquot (200 \(\upmu\)L) of the ethylene-glycol solutions in a vial, and the mixture was placed in a laboratory dryer at 40 \(\lx@math@degree\)C for 20 min.