To these mixes an addition of casein can be made (1% of weight of the lime) to increase fluidity if so required. If casein is added the water addition can be reduced between 25% and 50%. Obviously NHL 2 mixes are more fluid than NHL 3.5 or 5
Use a non-cavitating whisk (1500/2000 revs per minute) to ensure total homogenization.
GRAVITY FILL MORTAR.
Casein addition is possible (see above).
General: where open joints in the masonry show cavities, they should be marked as reference points. Point up open joints in masonry before grouting begins. Allow to settle and top up as necessary. Leave to cure for up to 3 or 4 weeks depending on the lime grout used before removing small areas of pointing to check the cavities are completely filled. Weep holes may be required to check the grout distribution.
The addition of casein will increase the compressive strength and the set whilst improving flow and reducing the water demand. Shrinkage, already low in NHL products and mortars, will be further reduced due to the lower water content of the grout.