How do you make hydraulic lime mortar?
We recommend the following procedure:
- Start with an empty mixer.
- Add 1 part sand.
- Mix in 1 part lime.
- Followed by 1.5 parts sand.
- Mix dry for at least 5 minutes.
- After 5 minutes slowly add water until the desired consistency is reached, it is very important not to drown the mix by adding too much water.
How is hydraulic lime manufactured?
A hydraulic lime is made from a limestone that either naturally contains or has artificially introduced some form of amorphous silica in the burning process. This amorphous or “free” silica fuses with some of the quicklime to form a clinker, a cementitious compound.
What is the difference between lime putty and hydraulic lime?
Lime putty can be made from either type of lime, and is made by adding an excess of water to quicklime. Hydraulic lime putty will set underwater within hours or days making them impractical, whereas non-hydraulic lime putty will remain plastic and improve with age.
What is hydraulic lime mortar?
Hydraulic lime is made from an impure limestone and sets through hydrolysis, a reaction caused by water. Hydraulic lime provides a faster initial set and greater compressive strength compared to non-hydraulic lime and will set in more extreme conditions including under water.
How long does hydraulic lime last?
4-12 months
Hydraulic lime mortars have a shelf life and should be stored dry and sealed from the atmosphere to prolong its life. If stored correctly, the bags of dry powder could last anything from 4-12 months from manufacture.
Can you mix hydraulic lime with cement?
Incorporating an appropriate proportion of hydrated lime into a cement-based mixture improves plasticity and workability, making the product easier to handle on the trowel. Hydrated lime also increases water retention which helps to improve the contact and bond with the substrate.
How long does hydraulic lime take to dry?
Properly mixed, placed and cured, they have great versatility, but should not be used in very demanding exposures such as copings, chimneys and pavings. Their initial setting time varies between four and 12 hours. Moderately to eminently hydraulic limes are not currently manufactured in the UK.
Is hydraulic lime waterproof?
Lightweight and weatherproof, the Sika Parex range of hydraulic lime-based renders can be used on painted surfaces of old or traditional buildings, the repointing of stonework and bricks, and for use as building mortar in constructing masonry.
How long does hydraulic lime mortar set?
Properly mixed, placed and cured, they have great versatility, but should not be used in very demanding exposures such as copings, chimneys and pavings. Their initial setting time varies between four and 12 hours.
What is the shelf life of hydraulic lime?
Most bagged, hydrated lime has a shelf life of 12 months once kept dry and sealed. Once opened bags should be used straight away or resealed so as to be airtight. Some premixed lime mortars with additives may have a shorter shelf life. Lime putty will last indefinitely once kept underwater and airtight.
Can you add cement to hydraulic lime?
A conventional cement mixer can be used to mix hydraulic lime plasters. However, for larger projects a roller-pan or paddle-mixer is preferable. Lime mortars mixed in drum mixers are prone to balling.