Instant history...after a little mixing.
If you mix it with sharp, gritty sand, you get a lime mortar which matches older mortar in houses or garden walls built before Portland cement became the norm. It mixes well in a concrete mixer or you can mix smaller amounts with a shovel or with a trowel and a bucket. The technical notes from Hanson recommend a ratio of 1 part lime to 2 parts sharp sand for a strong mortar or 1:3 for a general purpose mortar. They also advise using lime in temperatures above 5 degrees C and below 30 degrees C, which have been common in the past winter and summer heatwave.
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