Use of Fine-Ground Lava Sand as a Pozzolanic Additive in Aerial Lime-Based Mortars

conference paper

English

Pozzolanic additives were historically used in the construction practice to ensure improved mechanical properties and durability of the predominantly aerial-lime based mortars for the highly-stressed applications such as bridges, piers etc. The paper addresses the use of fine-ground lava sand as pozzolanic additive in aerial lime-based mortars. The mortars with 10%, 20%, and 40% lime replaced by the ground lava sand are studied regarding their strength properties, microstructure, and durability to freezing-thawing cycles and salt crystallization. The incorporation of ground lava sand to the mortar mixture leads to increase in strength by up to 50% in later ages. The pozzolanic reaction of the ground lava sand and lime along with the decrease in amount of aerial lime and kneading water in the mixture results in more unimodal pore distribution with lower total porosity, thus also lower water intake under atmospheric pressure. This change in microstructure combined with increased strength leads to mortars with improved durability to both, salt crystallization and freeze-thaw cycles. The fine-ground lava sand is found to be a suitable additive for aerial lime-based mortars to enhance their performance in building practice or to prepare mortars imitating the feeble hydraulicity of limes used in the past in constructions nowadays considered built heritage.

Durability; Fine-ground lava sand; Lime mortar; Microstructure; Pozzolan; Salt crystallization

ŽIŽLAVSKÝ, T.; VYŠVAŘIL, M.

13. 9. 2022

UNIVERSITY OF CANTABRIA

SANTANDER (SPAIN)

978-84-09-42253-1

Book of Articles of 9th Euro-American Congress on Construction Pathology, Rehabilitation Technology and Heritage Management, REHABEND 2022

1321

1326

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