ALKOXYSILANES AND THE CONSOLIDATION OF STONE PDF

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Get this from a library! Alkoxysilanes and the consolidation of stone. [George Wheeler; Getty Conservation Institute.]. Stone is one of the oldest building materials, and its conservation ranks as one of the most challenging in the field. The use of alkoxysilanes in the conservation. Permalink: ; Title: Alkoxysilanes and the consolidation of stone / George Wheeler ; with annotated bibliography by.

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Details Additional Physical Format: They have been reported to cause some slight changes in the color of treated stone, such as an initial darkening, i” and also formation of white spots on the stone. It must be non-corrosive and harmless in use.

The Conservation of Stone I. It was reported that the requisite degree of strengthening effect was produced for the previously very friable mudbrick and this eased the handling and prevented the damage which could alkoxydilanes occurred during reassembling and mounting the pieces to reconstitute the total mural.

Alkoxysilanes and the consolidation of stone (Book, ) []

Alkoxysilanes have received the most attention recently due to their successful performance as stone consolidants. The consolidated stone is expected to be consolkdation durable as the unweathered stone. Hydrolysis is the chemical reaction of an alkoxysilane with water or with the hydroxyl groups H on the surface of a mineral grain.

They have a good adhesion to stone and are resistant to water and several chemicals. Examples of thermosetting synthetic organic consolidatikn are epoxies, polyesters, and polyurethanes. National Bureau of Standards. The Conservation of Wooden Cultural property.

Alkoxysilanes and the consolidation of stone – Ghent University Library

Lima-Cusco PeruSepL When the solvent evaporates, the polymer remains in the stone. The author noted that although they all provided some consolidation, gave good penetration and produced little color change on the treated surface, it was X that gave consistentiy good ghe. Between andthe Centre per la Conservazione delle Sculture AH’aperto consolisation out a series of experimental testing of ten commercially available 60 stone consolidants applied to a calcitic Bologna sandstone.

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However, it was said to fade away during the following 12 months.

In the building industry, the markedly caustic nature of barium hydroxide tsone its major drawback since this may result in attack of other building materials including aluminum, zinc and glass. McDonald, ” Coatings, Sealers, Consolidants,” p. The use of inorganic materials as consolidants is an effort to produce a decay- resistant phase in the pores of deteriorated stone from aqueous solutions.

A consolidant should form a compact front against atmospheric pollutants, dust, biological agents, and wind at least for some time. They have been found effective in increasing the water repellency and the tensile strength of porous stone.

A solvent with hydroxyl groups -OH facilitates the cross-linking, whereas a solvent with a carbonyl group IZ: For a complete and 43 reliable laboratory evaluation, samples should represent the variety of decay processes. The crystal growth of barium carbonate or barium sulfate can also cause exfoliation, because these crystals have a larger molecular volume than the calcite crystals of calcareous stone and deteriorated stone might not accomodate these relatively large crystals. Consolidating and penetrating abilities of the consolidants, as well as their consolidatioon on the appearance and physical properties of the masonry substrate are evaluated.

Other tests alkooxysilanes for conslidation treated samples include: The Geological Society of America,p. Allow this favorite library to be seen by others Keep this favorite library private.

Partially polymerized ethyl silicate is widely marketed. Current literature on consolidation of deteriorated stone contains numerous projects which have utilized ethyl silicates as consolidants with significant success. An alkoxysilane consolidant is usually sprayed with low pressure or brushed thd to the substrate in repeated applications referred to as ” cycles ” by some manufacturers. Preliminary Investigations, ” in K.

Consolidation and Protection, p. The consolidating substance should have the ability alkoxysilaens penetrate easily and deeply into the weathered stone. Between anda variety of commercially teh silanes, which included X trimethoxymethylsilaneICI EP triethoxymethylsilaneWacker VP ethyl silicate and triethoxyethylsilaneand Tegovakon a material similar to the Wacker VPwere tested on a range of stones including Carrara marble, several English limestones and some English sandstones.

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The measured compressive strength and tensile strength of treated and untreated masonry samples are compared to estimate the improvement in the mechanical properties of masonry following consolidation and to determine the consolidating abilities of the consolidant o Salt Crystallization: The Geological Society of America,pp. Carbonation of the stone surface results from the reaction of the barium hydroxide with atmospheric carbon dioxide, whereas carbonation of the interior of the stone takes place consolixation the reaction of barium hydroxide with carbon dioxide which is released during the hydrolysis of urea.

It is this silicic acid that is considered responsible for the consolidation of stone. Thereforc, they are usually dissolved in organic solvents to reduce the viscosity. Acrylic Polymers 13 1. These requirements may be encapsulation of salts or extraction of salts from stone, prevention of further microbiological growth, providing water repellency, reversibility to allow future treatment, etc.

Alkoxysilanes and the consolidation of stone

Recent Experiments with Alkoxysilanes in Stone Consolidation 56 3. The presence of solvents has an essential influence on the speed of the cross-linking reaction which should take place slowly to gain time for the diffusion of the resin molecules into the pores of stone.

After epoxy resin impregnation, the resin tends to migrate back to the surface as the solvent evaporates.

Another report by S. Consolidation should not be considered as a single operation. Fluorocarbon-acrylic copolymers, however, are generally avoided in conservation practice today.

The evaporation of liquid monomer has also been found to be RH dependent. In addition, problems can be faced regarding the total penetration of most stone consolidants when large sized test samples required by some ASTM standard test methods are cosolidation. Linked Data More info about Linked Data. The effectiveness of a consolidation treatment depends on the proper selection of the consolidating substance, what is expected of it and how it is used.