Gilles Mertens

Hydraulicity in Historic Lime Mortars: A Review

Natural hydraulic limes were used in ancient times and are still produced today. A comparison of the chemistry and mineralogy of currently available NHL2 and NHL5 limes indicate that there are no clear differences except for the amount of ‘undefined material’, mainly comprising an amorphous phase. The chemical composition of these different limes is nearly identical. However, the classification of ancient hydraulic limes is mainly based on their chemistry, obtained from the analysis of ancient mortar binders. Moreover, it is shown that the phase composition of these limes evolves with time, making their classification uncertain and difficult.

Raw materials used in ancient mortars from the Cathedral of Notre-Dame in Tournai (Belgium)

Abstract: Mortar samples from the Notre-Dame Cathedral at Tournai in Belgium have been investigated as part of a broader studyconsidering the transition of ancient cities and their rural territories from Roman to late Roman society and the transformation to theearly Middle Ages. Masonry mortars and mortars used for flooring have been studied from the Imperial Roman period, theCarolingian style period and the Romanesque style period (4th–11th century AD).A selected set of samples has been characterised using a combination of mineralogical, chemical and microscopical techniques.This characterisation enabled us to refine our knowledge of the mortar composition, of the original materials and of their provenance.It appears that both chalk and ‘‘hard’’ Tournaisian limestone were used to produce the lime. Both locally available materials can yieldeither hydraulic or non-hydraulic lime. The aggregates have a local origin. Additionally, several microscopical techniques wereapplied to identify the nature of the overburnt particles. The low abundance of this type of Binder Related Particles in the Gallo-Roman and Palaeo-Christian mortars suggests that technological knowledge, be it empirical or theoretical, was available.Key-words: ancient mortars, raw materials, provenance, lime binder, lime burning, hydraulicity, archaeometry.

Study of composition change and agglomeration of flue gas cleaning residue from a fluidized bed waste incinerator

Blocking of the collection hoppers of the baghouse filters in a fluidized bed incinerator for co‐incineration of high calorific industrial solid waste and sludge was observed. The composition of the flue gas cleaning residue (FGCR), both from a blocked hopper and from a normal hopper, was investigated by (differential) thermogravimetric analysis, quantitative X‐ray powder diffraction and wet chemical analysis. The lower elemental carbon concentration and the higher calcium carbonate concentration of the agglomerated sample was the result of oxidation of carbon and subsequent reaction of CO2 with CaO. The evolved heat causes a temperature increase, with the decomposition of CaOHCl as a consequence. The formation of calcite and calcium chloride and the evolution of heat caused agglomeration of the FGCR. Activated lignite coke was replaced by another adsorption agent with less carbon, so the auto‐ignition temperature increased; since then no further block formation has occurred.

Halloysite occurrence at the karstified contact of Oligocene sands and Cretaceous calcarenites in Hinnisdael quarries, Vechmaal (NE of Belgium)

1. Introduction Halloysite is a dioctahedral 1:1 clay mineral of the kaolinite group frequently discussed in literature because of its potential for nanotechnological applications (Keeling, 2015; Yuan et al., 2015; Yuan et al., 2016). Its geological occurrence has been primarily linked to soil and weathering environments, by the weathering and alteration of volcanic rocks (Vaughan et al., 2002; Velde & Meunier, 2008), the alteration of clay minerals like montmorillonite or biotite (Hill, 2000; Papoulis et al., 2009) or weathering of feldspars (Sheets & Tettenhorst, 1997; Adamo et al., 2001). Halloysite is also a common mineral constituent in karst and paleokarst environments as a result of acid weathering (Polyak & Guven, 2000; Joussein et al., 2005). In Belgium, halloysite was reported in over 30 localities, almost all with a very similar geological setting, i.e. karstified carbonate substrates filled up by Cenozoic sand deposits (Buurman & Van der Plas, 1968; Dupuis & Ertus, 1995; Goemaere & Hanson, 1997; Nicaise, 1998; Kloprogge & Frost, 1999; De Putter et al. 2002; Bruyere, 2004). A similar geological setting is found inside the underground quarries of Hinnisdael, locally known as “mergelgrotten” (“marl caves”), located in Vechmaal, Limburg province, Belgium (Fig. 1). In two of the Hinnisdael underground quarries, dolines filled with marine sand were intersected and an irregular white clay layer occurs at the contact between the karstified top of the Cretaceous calcareni

NEWMOD-2 - A Computer Program for Qualitative and Quantitative 1-D X-ray Diffraction Pattern Modeling

NEWMOD-2 is a state of the art software package with a user friendly GUI, to model one-dimensional X-ray diffraction patterns of clay minerals or mixtures of clay minerals. Both quantitative and structural information is deduced from the model.

Better Understanding Shales by Accurate Qualitative and Quantitative Mineralogy

A thorough characterization of the mineralogy and detailed clay mineralogy is an important tool in scientific research and industrial applications of shales. It helps to understand the geological history of the deposits and significantly contributes to solving specific geological problems. In three separate examples, it is demonstrated how the clay mineralogy of fine-grained deposits during different stages of diagenesis is characterized in detail. In a first example, clay minerals are used as provenance indicators in recent muds of the Belgian North Sea. A second example handles on the detailed clay mineralogy of early diagenetic Ypresian clays which are currently being researched as possible host rock for radioactive waste disposal. A third example involves the mineralogical characterization of a later diagenetic potential shale gas play in Belgium.

The pozzolanic reaction between clinoptilolite and portlandite: a time and spatially resolved IR study

The pozzolanic reaction of a natural zeolite-rich tuff and portlandite was investigated by means of IR spectroscopy. The zeolite tuff consisted mainly of Ca-rich clinoptilolite. A detailed analysis of the changes in the bonding environment during reaction presented by the IR spectra showed that the vibrations assigned to the reactant phases were progressively consumed and implied that Si-rich environments were preferentially depleted. The contemporaneous appearance and rise of vibration bands characteristic for calcium-silicate-hydrates and calcium-aluminate-hydrates demonstrated the formation of reaction products. Changes in bonding environment were spatially visualized by means of synchrotron-IR microspectroscopy. Promising results showed the distribution of reactants and reaction products and allowed to analyze spatial trends in IR-vibration frequencies. A shift in calcium-silicate-hydrate mean peak position from 972 to 968 cm −1 indicated a decrease in silicate chain length with increasing distance from the clinoptilolite-matrix interface.