This type of analysis measures the characteristics of the mortar by acid digestion. In addition to the physical proportion acid digestion also provides data about chemical reactivity. Comparing this measurement to our extensive control data provides very useful insight into the relative proportion of lime to cement that has actually reacted. Based on evaluation of this data we can provide approximate formulations of original historic mortar in terms of modern materials and confidently recommend an appropriate replacement mortar.
This test is not recommended for establishing the proportions of modern mortars with a high degree of accuracy as the very low unbound lime content makes acid digestion difficult.