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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When choosing a solvent and catalyst to increase the rate of polymerization, one should be aware of the fact that they must not react with the substrate and leave any soluble residue in it which can cause future decay. Inorganic and Metal-Organic Compounds, ” p. Applications were a few days apart In sone, a series of injections of an acryUc emulsion were made through the preexisting cracks to strengthen the inner part of the wall.
On the other hand, Rolf Wihr advocated the use of a spray system providing a continuous rain of consolidant and recirculating run off material in order to obtain a deeper penetration, based on observation that stone gradually becomes fully soaked in rain. Acrylic Polymers 13 1. The earliest attempt to use silicic ether or ethyl silicate for stone conservation was made in an meeting of the Royal Institute of British Architects by A.
Getty Publications Virtual Library. A Long-Term Evaluation,” pp. The other drawbacks of waxes are their tendency to soften at high temperatures and to collect dirt. Since Brethane was a newly ztone consolidant, its use was recommended only for cases where decay was advanced.
When necessary, absorbent pads of tissue should be placed below the treatment area to prevent excess silane al,oxysilanes running down. Zinsmeister, Conservation of Natural Stone: Alkoxysilane-based formulations have since become the material of choice for the consolidation of stone outdoors.
The alkoxy groups R of alkoxysilanes are capable of reacting with hydroxyl groups. A Review of Natural Stone Preservation.
Don’t have an account? As a consequence of the combined effects of chemical and mechanical weathering, stone can lose its cohesion to such a degree that its physical survival is imperilled and a treatment is necessary to restore its integrity. Horie, Materials fo r Conservation: A certain optimism has resulted fix m increased research on the development of different techniques and the materials themselves.
It is the siUcon-oxygen-silicon linkages that produce the off and strengthening effect.
Although the chemical affinity of silanes for calcareous stones is minimal, a network of polymer may fill the intergranular spaces of the stone and having a consolidating effect without forming a chemical bridge between the grains.
Siliceous consolidants and alkaline earth hydroxides are the primary inorganic 3 materials used in stone consolidation. Inorganic and Metal-Organic Compounds,” in L. Several types of stone, brick and clay have reactive hydroxyl groups on their surface.
During handling or application, a consolidant should not introduce health and safety hazards. Besides providing a short-term evaluation of the recommended consolidation treatment slaboratory programs have the advantage that test conditions can be adjusted to simulate the specific environment and climate to which the consolidant will be exposed.
Details Additional Physical Format: Restoration and Preservarinn Ethingen bei Boblingen: Preprints of the Contributions to the Paris Congress, September The amount of consolidant deposited in each of the treated masonry samples is determined to evaluate the effectiveness of the treatment and efficiency of the application procedures.
The product was reported to reduce the rate of stone decay very substantially. However, they do not penetrate easily into small pores due to the large size of their molecules and tend to accumulate near the surface.
What makes the alkoxysilanes so attractive is that some of them, notably the alkylalkoxysilanes and silicic acid esters, meet several of the performance requirements.
A study on the polmerization of methyl methacrylate in sandstone by P. After more than twenty years of experience, alkoxysilanes have so far proved to be effective for the consolidation of sandstones, limestones and earthen building materials. Furthermore, on-site testing sgone the rate of application, rate of consumption and exact application procedures to be used under field conditions, such as the number of applications and how the products are applied.
Chemical Structure of Alkoxysilanes 31 2. However, it is extremely difficult to control relative humidity in the field.
Alkoxysilanes and the consolidation of stone
The following tests are recommended for a comprehensive and reliable laboratory evaluation of untreated masonry samples to determine the suitability of the masonry for consolidation treatment: Elsevier Science Publishers B. Partially polymerized ethyl snd is less expensive than monomeric ethyl silicate.
Alkoxysilanes and the Consolidation of Stone. The stone consolidants reviewed in this chapter are divided into four groups according to their chemistry.
Full text of “Alkoxysilanes consolidation of stone and earthen building materials”
Preview this item Preview this item. The following tests are suggested for the laboratory evaluation of treated masonry samples: Ef oxies have been used to consolidate limestone, sandstone, and marble in addition to their use as adhesives, paints, varnishes, and constituents of synthetic mortars and concrete.
This phase of the test wall project is scheduled for completion in These products are in the form of one-pack materials.
Authors theorize that a slow dehydration takes place which takes the clay to a form that prevents the water-based curing mechanism from occuring. In response to this, numerous research projects, publications and conferences dealing with stone have been facilitating the worid wide exchange of information.
The deposition, that will bind stone particles together, can result from evaporation of alkoxysiilanes solvent or chemical reactions with the stone.
Torraca indicates that Paraloid B shows a good resistance to the ageing process and its life span is years alkoxyailanes external exposure.
They polymerize by means of heating with o initiator, ultraviolet radiation or gamma radiation. Consolidation a nd Protectionp. Controversy in the publications over the use of alkoxysilanes on stone and adobe conservation might partially result from the lack of research and an incomplete understanding of the complexity of alkoxysilane chemistry.