Umweltgeologische Evaluierung von Entsorgungs- und Verwertungsmöglichkeiten für Tunnelausbruchsmaterial im Rahmen des FCC-Projekts

Research output: ThesisMaster's Thesis

Authors

Abstract

The master's thesis is dedicated to the environmental geological assessment of disposal and recycling options for tunnel excavation material in the FCC project. The main focus was on a comparative analysis of the legal frameworks and experimental investigations in Austria, Switzerland, and France. Chemical analysis of two samples (qSTP1 and qSTP2) from initial boreholes was conducted, evaluating their potential for reuse in various industries based on technical and legal requirements. Total contents (metals after aqua regia digestion and total digestion, as well as X-ray fluorescence) and eluate contents were determined for the analyses. A comparison of the results of qSTP1 and qSTP2 with retained samples from previous work confirmed the representativeness of the drawn samples. The composition of the X-ray fluorescence analysis revealed the presence of the following main components: 47% SiO2, 12% CaO, 11% Al2O3, 7% MgO, 5% Fe2O3, 2% K2O, and 1% Na2O. X-ray diffraction (XRD) examination identified the following phases: 20% CaCO3 (calcite), 19% KAl2[(OH,F)2|AlSi3O10] (mica group (muscovite/illite)), 14% (Fe,Mg,Al)6(Si,Al)4O10(OH) (chlorite), 12% NaAlSi3O8 (plagioclase (albite)), 11% SiO2 (quartz), 11% CaMg(CO3)2 (dolomite), 11% (Ca,Na,K)(Mg,Fe,Al)9(Si,Al)8O20(OH)10 nH2O (corrensite), and 4% KAlSi3O8 (potassium feldspar (microcline)). According to the landfill ordinance, the tunnel excavation material is considered non-hazardous waste and complies with the limits for construction waste landfills and mass waste landfills. However, this is the least favorable disposal method. According to the Federal Waste Management Plan, the tunnel excavation material does not meet any quality class. However, it complies with the limits of the Austrian Recycling Construction Material Ordinance (aggregate for recycled asphalt or for unbound top layer according to § 13 Z 9), although the use of the material is currently not allowed for legal reasons. In Switzerland, the tunnel excavation material meets the limits according to the Ordinance on the Avoidance and Disposal of Waste (VVEA) and is classified into categories Type D and Type E. According to Étarès Environnement, in France, the tunnel excavation material meets the limits for Class 2 as well as for Class 3. Due to the large quantity (9 million m3) and possible variations in material composition, industries that can only use the tunnel excavation material in small quantities were treated as lower priority. This also applied to industries with low tolerance to variations in the quality and composition of their raw materials. The evaluation of the tunnel excavation material in the context of the master's thesis results in the following conclusions: The tunnel excavation material shows potential as a substitute raw material for use in the cement industry due to high quantities of main raw materials such as SiO2, CaO, Al2O3, and Fe2O3. In the brick industry, it could be used for masonry brick masses, but elevated magnesium and calcium oxide contents could cause problems, limiting its use to an aggregate. It is unsuitable for the glass industry due to high contamination levels (e.g., iron). In agriculture, it is unsuitable due to high nickel concentrations and limited nutrient content.

Details

Translated title of the contributionEnvironmental geological evaluation of disposal and recycling options for excavated tunnel material within the FCC-project
Original languageGerman
QualificationDipl.-Ing.
Awarding Institution
Supervisors/Advisors
Award date22 Mar 2024
DOIs
Publication statusPublished - 2024