Curing Compounds and Additives

Curing compounds are sprayed onto fresh concrete surfaces to retain moisture and ensure proper strength development.
Common types include resin-based, wax-based, and acrylic curing compounds each with different application methods.
Some curing compounds contain volatile organic compounds (VOCs) that are harmful when inhaled in enclosed areas.
Concrete additives such as accelerators, retarders, plasticisers, and air-entraining agents modify concrete properties.
Accelerator chemicals may contain calcium chloride or lithium compounds that irritate skin and eyes on contact.
The COSHH Regulations 2002 require assessment of all curing compounds and additives used on site.
Spray application of curing compounds creates aerosol mist that requires RPE and eye protection.
Mixing additives at incorrect dosages affects concrete strength, durability, and structural performance.
Safety data sheets must be available for every curing compound and additive product used on site.
Spills of curing compounds and additives can contaminate soil and water if not contained and cleaned up.

Protect your health	VOC-containing compounds and chemical additives cause respiratory irritation, skin burns, and eye damage.
Quality assurance	Incorrect application of curing compounds or additive dosages leads to structural defects and costly remedial work.
Legal compliance	COSHH 2002 requires risk assessment, safe handling procedures, and PPE provision for all chemical products.

Do

Don't

Read the safety data sheet for every curing compound and additive before first use
Complete a COSHH assessment for each product and brief workers on the required controls
Wear RPE with an organic vapour filter when spray-applying VOC-based curing compounds
Use eye protection and chemical-resistant gloves when handling all chemical additives
Apply curing compounds at the coverage rate specified by the manufacturer for effectiveness
Ensure adequate ventilation when using curing compounds or additives in enclosed areas
Store all chemicals in labelled containers in designated, bunded storage areas on site
Measure additive dosages accurately using calibrated equipment as specified in the mix design
Clean up spills immediately using absorbent materials and contain runoff from reaching drains
Dispose of empty containers and waste chemicals as controlled waste through licensed carriers

DON'T spray curing compounds without RPE when working in enclosed or poorly ventilated areas
DON'T handle chemical additives with bare hands — wear chemical-resistant gloves at all times
DON'T alter additive dosages from the approved mix design without the engineer's authorisation
DON'T store incompatible chemicals together or near food and drinking water supplies
DON'T apply curing compounds in windy conditions where overspray affects adjacent workers
DON'T wash curing compound equipment into site drainage or watercourses
DON'T use expired or degraded curing compounds that may not perform to specification
DON'T ignore skin or eye contact — flush immediately with water for at least 15 minutes
DON'T smoke near solvent-based curing compounds as they are flammable when wet
DON'T assume all curing compounds are the same — check the SDS for specific hazards

See also: Concrete Pour Safety | COSHH Awareness

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