Non-Hydraulic Lime Mortars

Abstract Lime-based mortars are now widely acknowledged as generally superior to cement-based mortars in the repair of appropriate historic infrastructure. Increasingly the benefits of hydraulic lime mortars are also being realized in new masonry construction. In order to standardize the expected performance of mortars, designers will specify the type of lime, the type of filler (aggregate), the proportions of each and quantity of water or the required workability. Limes can be non-hydraulic (calcium or dolomitic) or hydraulic (natural or artificial). This paper reports on results of tests conducted on non-hydraulic lime conservation repair mortars at early stages of curing. Results to date show that the type of both non-hydraulic lime and filler used have a significant effect on the early (up to 28 days) mechanical performance of a lime mortar. The mortars in the study were made using five non-hydraulic lime binders: dry hydrate; 4 month-old lime putty; 20 year-old lime putty; ‘hot’ lime; and dispersed hydrated lime. The fillers were silicate sand, crushed bioclastic limestone, and crushed oolitic limestone. No pozzolanic material was added to the mortars. Compressive strengths at 14 days ranged from 0.3 MPa to 2.5 MPa. Comparisons are made between the structural performance and rates of carbonation up to 28 days of each binder:aggregate combination. In conclusion, observations are made on factors to be considered when specifying non-hydraulic lime mortar mixes for repair work.

[1]  F. Tasselli,et al.  A Study of the Hydration of Lime-Pozzolan Binders , 1998 .

[2]  A. Moropoulou,et al.  Evaluation of pozzolanic activity of natural and artificial pozzolans by thermal analysis , 2004 .

[3]  Richard Glover,et al.  Field and Laboratory Assessment of Lime-Based Mortars , 2001 .

[4]  Jeanne Marie Teutonico,et al.  The Smeaton project: factors affecting the properties of lime-based mortars , 1993 .

[5]  Alec Clifton-Taylor,et al.  The pattern of English building , 1972 .

[6]  Christopher Brereton,et al.  The Repair of Historic Buildings: Advice on Principles and Methods , 1995 .

[7]  H. K. Cammenga.  Thermal Analysis — Techniques and Applications. Herausgegeben von E. L. Charsley und S. B. Warrington. The Royal Society of Chemistry, Cambridge, 1992 , 1994 .

[8]  D. D’Ayala,et al.  Determination of carbonation profiles in non-hydraulic lime mortars using thermogravimetric analysis , 2006 .

[9]  J. Lanas,et al.  Masonry repair lime-based mortars: factors affecting the mechanical behavior , 2003 .

[10]  Giuseppe Cultrone,et al.  Aging of Lime Putty: Effects on Traditional Lime Mortar Carbonation , 2004 .

[11]  A. Przepiera,et al.  Thermal transformations of selected transition metals oxyhydroxides , 2003 .

[12]  Bernard Melchior Feilden,et al.  Conservation of historic buildings , 1984 .

[13]  Koenraad Van Balen,et al.  Modelling lime mortar carbonation , 1994 .

[14]  K. Van Balen,et al.  Carbonation reaction of lime, kinetics at ambient temperature , 2005 .

[15]  Y. Cai,et al.  Study of chloride binding and diffusion in GGBS concrete , 2003 .