This standard outlines the recommended practices for handling and applying silicate-based mortars that resist chemical attack, focusing on storage, mixing, surface preparation, curing, and chemical compatibility. It is designed for professionals engaged in acid-resistant flooring and wall linings using silicate mortars combined with acid-proof bricks or tiles in harsh chemical environments.
Overview
This standard outlines the recommended practices for handling and applying silicate-based mortars that resist chemical attack, focusing on storage, mixing, surface preparation, curing, and chemical compatibility. It is designed for professionals engaged in acid-resistant flooring and wall linings using silicate mortars combined with acid-proof bricks or tiles in harsh chemical environments.
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Frequently Asked
The code does not specify exact mix ratios but advises against adding Portland cement or water to silicate mortars. Mixing involves initially combining about 75% filler with the liquid binder, followed by the remainder of the filler until a uniform paste forms. The quantity mixed should be limited to what can be applied before setting. For precise proportions, refer to IS 4832 (Part I)-1969 or manufacturer's directions. Application thickness is generally 6 to 8 mm with joint widths not exceeding 6 mm.
Surfaces must be thoroughly cleaned, dry, and properly cured before mortar application, ensuring no contamination from cement, water, dust, or grease since silicate mortars must not contact cement concrete. Mortars should be applied 6 to 8 mm thick on tile or brick backs and sides, with joint widths between 2 and 6 mm depending on location. Mortar should be removed from joints to a 20 mm depth before final filling to ensure strong adhesion and durability.
Acid curing involves applying 20-25% hydrochloric acid or 30-40% sulphuric acid solutions no earlier than 2 days and no later than 6 days after bonding, for a minimum of 60 minutes. Acid solutions must be prepared by adding acid to water. If epoxy, polyester, or sulphur mortars are used for jointing, acid curing is not required; however, phenolic, furane, or cashewnut shell liquid jointing mortars necessitate acid curing. Protection from water and rain during curing is essential, with minimum curing times ranging from 24 to 48 hours.
Silicate mortars generally withstand alkalis, mild acids, and neutral salt solutions effectively. However, they are not recommended for use with strong acids such as concentrated hydrochloric or sulphuric acid and other aggressive chemicals, as these degrade the mortar binder. Proper curing and adherence to temperature guidelines during mixing and application are critical to maintaining chemical resistance.
No, silicate mortars must not be mixed with Portland cement or water, nor should they come into contact with cement concrete surfaces. They require independent application without cement contamination to ensure proper bonding and durability. This is emphasized to maintain the chemical resistance and structural integrity of the mortar according to the standard.
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