Low energy pre-blended mortars: Part 1 – Control of the sand drying process using a lime drying technique

Low energy pre-blended mortars: Part 2 – Production and characterisation of mortars using a novel lime drying technique

“…Two different quicklimes, C1 and E, were used for the preparation of the lime-dried mortars. The chemical and physical properties of these materials, together with properties of the slaked limes, were reported in Part I of this study [1]; Table 1 summarises the key properties of the slaked limes and a commercial CL90 which has been used as a control. ggbs was supplied by Civil & Marine Slag Cement from the Frodingham plant, UK.…”

“…Free lime (% CaO) [1] shows that the optimum stoichiometric ratio for quicklime addition to dry the sand decreases with increases in either the sand moisture content or the mixing time of the wet sand and quicklime. This is represented for lime E in Figure 1 by the 3 linear relationships.…”

“…The associated values of stoichiometric ratio and sand free moisture content for both ggbs/CH ratios have been superimposed on Figure 1 and the intersection of the relationships indicates the optimum drying conditions for each mortar; the 4 mortars using quicklime E detailed in Table 2 are indicated on Figure 1. The same approach was adopted for mortars using quicklime C1 In accordance with the terminology previously described [1] all mortars are considered optimally dried. All mortars were produced at a constant sand:binder ratio of 2.25:1 by volume.…”

“…5, 10 or 15 min). Following mixing, the lime-dried materials were stored in sealed containers for 24 hours to ensure complete hydration of the quicklime; this step was included after previous observations indicated the presence of free water in the blend at the completion of the initial mixing [1]. The required quantity of ggbs was then added in order to provide the desired mix proportions.…”

“…The first part of this paper [1] described a technique by which the addition of quicklime to wet sand could be controlled to produce Formulated Lime mortars which are dry and suitable for long-term storage in silos or bags prior to final wet mortar production. The principal process-control factors to achieve optimal drying have been identified as lime addition based upon a fraction of the stoichiometric requirement for complete slaking of the quicklime (i.e.…”