Code of practice for the use of resin-type chemical-resistant mortars
1980 Edition

Recommended storage durations for resin mortars vary by type: cashew-nut shell liquid should be stored up to 9 months, epoxy and furane up to 12 months, while phenolic and polyester have a shorter shelf life of about 3 months. Curing times before usage also differ; furane, epoxy, and polyester require a minimum of 48 hours at temperatures above 20°C. Phenolic and cashew-nut shell liquid resins need longer curing periods ranging from 7 to 28 days without heat, which can be reduced significantly with heat treatment using infrared lamps. It is essential to protect the mortar from moisture, weather, and mechanical damage during curing, and to maintain proper environmental temperatures to ensure quality.

For mixing resin-type chemical resistant mortars, pour the specified amount of liquid resin into a container and gradually add the powder component, stirring thoroughly with a stainless steel spatula to avoid lumps and air pockets, following manufacturer-specified ratios. When applying to floors, spread a 6 to 8 mm thick layer on the back of tiles or bricks, smear 4 to 6 mm on two adjacent sides, press firmly onto the substrate maintaining 2 to 3 mm joints, trim excess mortar, and allow full hardening before acid curing (except for epoxy and polyester resins). For wall applications, use similar thicknesses and side smearing, press tiles against the wall and adjacent units, maintain the same joint width, trim excess, and lay only one course initially to prevent slippage, allowing joints to set before continuing. Acid curing applies similarly except for epoxy and polyester mortars.

Resin mortars exhibit varying degrees of resistance depending on the resin type and chemical exposure. Epoxy mortars generally provide excellent resistance to acids such as acetic, hydrochloric, and sulphuric acids but are not suitable for concentrated nitric acid or hydrofluoric acid unless formulated with specific fillers. Phenolic and furane resins show good resistance to many acids and alkalis but have limitations with oxidizing agents. Polyester and cashew-nut shell liquid mortars have limited resistance to certain solvents and alkalis. Oxidizing wet gases are generally not recommended for any resin type, while reducing wet gases are tolerated. It is advisable to consult chemical resistance tables and manufacturer guidance to select the appropriate resin mortar for specific chemical environments.

When working with resin mortars, it is crucial to observe strict safety protocols. Inflammable resin mortars must be handled with appropriate fire safety precautions, avoiding ignition sources and ensuring adequate ventilation to manage fumes during mixing and curing. For confined spaces, forced ventilation is recommended. Personal protective equipment such as gloves or barrier creams should be used to prevent skin irritation. Resin mortar residues on skin should be removed immediately by wiping with cotton waste followed by washing with warm soap water or specialized cleansing agents; solvent use on skin is discouraged. Proper storage and adherence to manufacturer guidelines are essential to prevent accidents and ensure safe handling.

Curing durations depend on both the resin type and environmental temperature. Furane, epoxy, and polyester mortars typically require a minimum curing period of 48 hours at temperatures of 20°C or higher before they can be put into service. Phenolic and cashew-nut shell liquid resins require extended curing times ranging from 7 to 28 days without heat, which can be shortened by using infrared heat treatment to 2 days for phenolic and 6 days for cashew-nut shell liquid. At temperatures below 15°C, it is necessary to warm masonry units and maintain the curing environment above 15°C using infrared lamps or other heating methods to ensure proper curing, often resulting in longer curing times as recommended by manufacturers.