Mortar ratios: How to measure void space in sand

The basic idea behind determining the void space in a sand is to determine the ratio of lime needed to adequately bind the sand without pushing the sand grains apart. In other words, how to make the strongest possible mortar by optimizing the lime portion.

A Tale of Three Sands or What Type of Sand makes for Strong Mortars?

The right qualities of sand are crucial in lime mortar making and differ some from brickwork versus plaster and stucco. The increasing inclusion of crushed rock in sand mixes presents particular problems.