Natural zeolite as a binder and aggregate: The path to sustainable repairs of historic lime mortars

Natural zeolite as a binder and aggregate: The path to sustainable repairs of historic lime mortars

Článek WoS

The protection of historic buildings requires the use of traditional building materials that are as compatible as possible with the historic materials. Air lime mortars are not suitable for use in damp environments due to their non-hydraulic properties and low frost resistance. Significant changes in the properties of air lime mortars can be achieved by the addition of pozzolanic admixtures or aggregates with pozzolanic properties. The paper aims to describe the effects of partial lime replacement with finely ground natural zeolite on the mechanical, microstructural and durability properties of air lime mortars lightened with coarse natural zeolite that meet the functional and technical criteria imposed on repair mortars. Mortars were prepared with 10%, 20% and 40% lime replacement by fine zeolite, quartz sand replacement by coarse zeolite of the same granulometry and a combination of these two replacements and their fresh properties (bulk density, air content, water retention), compressive and flexural strengths, porosity, water absorption, capillary water suction, frost resistance, and salt crystallization resistance were compared with the reference lime mortar. The use of lightweight zeolite aggregate in the composition of mortars led to their higher porosity, lower density, improved capillary suction and water absorption, and increased salt accumulation, while the replacement of lime with fine zeolite resulted in an increase in the strength and frost resistance of the prepared mortars. Mortars with a combination of replacing part of the lime with fine zeolite and sand with coarse zeolite showed the best mechanical properties. The resistance of the mortars to salt crystallization using Na2SO4, NaCl and NH4NO3 solutions was improved. In terms of compatibility, functional and technical criteria, lime-zeolite lightweight mortars can be classified as repair mortars, particularly suitable for dewatering and desalinating of masonry. An undeniable advantage of these mortars is their lower carbon footprint compared to air lime or natural hydraulic lime mortars.

The protection of historic buildings requires the use of traditional building materials that are as compatible as possible with the historic materials. Air lime mortars are not suitable for use in damp environments due to their non-hydraulic properties and low frost resistance. Significant changes in the properties of air lime mortars can be achieved by the addition of pozzolanic admixtures or aggregates with pozzolanic properties. The paper aims to describe the effects of partial lime replacement with finely ground natural zeolite on the mechanical, microstructural and durability properties of air lime mortars lightened with coarse natural zeolite that meet the functional and technical criteria imposed on repair mortars. Mortars were prepared with 10%, 20% and 40% lime replacement by fine zeolite, quartz sand replacement by coarse zeolite of the same granulometry and a combination of these two replacements and their fresh properties (bulk density, air content, water retention), compressive and flexural strengths, porosity, water absorption, capillary water suction, frost resistance, and salt crystallization resistance were compared with the reference lime mortar. The use of lightweight zeolite aggregate in the composition of mortars led to their higher porosity, lower density, improved capillary suction and water absorption, and increased salt accumulation, while the replacement of lime with fine zeolite resulted in an increase in the strength and frost resistance of the prepared mortars. Mortars with a combination of replacing part of the lime with fine zeolite and sand with coarse zeolite showed the best mechanical properties. The resistance of the mortars to salt crystallization using Na2SO4, NaCl and NH4NO3 solutions was improved. In terms of compatibility, functional and technical criteria, lime-zeolite lightweight mortars can be classified as repair mortars, particularly suitable for dewatering and desalinating of masonry. An undeniable advantage of these mortars is their lower carbon footprint compared to air lime or natural hydraulic lime mortars.

Durability; Lightweight aggregate; Lime mortar; Porosity; Pozzolanic reaction; Repair of historic building; Zeolite

Durability; Lightweight aggregate; Lime mortar; Porosity; Pozzolanic reaction; Repair of historic building; Zeolite

VYŠVAŘIL, M.; ŽIŽLAVSKÝ, T.; BAYER, P.

15.06.2026

Elsevier BV

Construction and Building Materials

537

Spojené království Velké Británie a Severního Irska

147076

14

https://www.sciencedirect.com/science/article/pii/S0950061826019847