View in EDS

Influence of the clay/cement ratio on the water durability of tuff-based mortars: mineralogical, microstructural, and mechanical correlations.

Saved in:
Bibliographic Details
Title: Influence of the clay/cement ratio on the water durability of tuff-based mortars: mineralogical, microstructural, and mechanical correlations.
Authors: Feredj, Bouabdellah1 (AUTHOR), Abou-Bekr, Nabil1 (AUTHOR), Bencheikh, Mohamed2 (AUTHOR), Boulekbache, Bensaid3 (AUTHOR) b.boulekbache@univ-chlef.dz, Ait Atmane, Hassen4 (AUTHOR), Safer, Omar5 (AUTHOR)
Source: Geomechanics & Geoengineering. Jun2026, Vol. 21 Issue 3, p671-688. 18p.
Subject Terms: *Water damage, *Mortar, *Microstructure, *Compressive strength, *Mechanical behavior of materials, *Mineralogical chemistry
Abstract: This study assesses the water durability of tuff-based mortars stabilised with clay and cement. Three formulations are tested: M1 (15% cement, 10% clay), M2 (10% cement, 15% clay), and M3 (5% cement, 20% clay). The results demonstrate a predominant influence of the clay/cement ratio. Formulation M1 exhibits the best performance, with a 28-day compressive strength of 8.15 MPa, a low capillary absorption coefficient (Cb of 9.78 g/cm2.min0.5), and minimal mass loss (7.28%) after 12 drying – wetting cycles. In contrast, mortar M3, which is richer in clay, exhibits poor compressive strength (2.97 MPa), strong capillarity (Cb = 19.24 g/cm2.min0.5), and significant degradation (20.88% mass loss). A paradox is resolved: although the literature indicates that the identified clay minerals (kaolinite/muscovite) are typically associated with low cation exchange capacity and limited swelling potential, the fine fraction of the clay induces textural swelling and destructive capillary pressures during hydraulic cycles. SEM-EDS analyses reveal a heterogeneous microstructure with impurities (Fe, K) that may intensify degradation. The durability is governed by the composite microstructure rather than mineralogy alone. Cement content greater 15% is essential to ensure the long-term stability of earth-based mortars. [ABSTRACT FROM AUTHOR]
Database: Energy & Power Source
Description
Abstract:This study assesses the water durability of tuff-based mortars stabilised with clay and cement. Three formulations are tested: M1 (15% cement, 10% clay), M2 (10% cement, 15% clay), and M3 (5% cement, 20% clay). The results demonstrate a predominant influence of the clay/cement ratio. Formulation M1 exhibits the best performance, with a 28-day compressive strength of 8.15 MPa, a low capillary absorption coefficient (Cb of 9.78 g/cm2.min0.5), and minimal mass loss (7.28%) after 12 drying – wetting cycles. In contrast, mortar M3, which is richer in clay, exhibits poor compressive strength (2.97 MPa), strong capillarity (Cb = 19.24 g/cm2.min0.5), and significant degradation (20.88% mass loss). A paradox is resolved: although the literature indicates that the identified clay minerals (kaolinite/muscovite) are typically associated with low cation exchange capacity and limited swelling potential, the fine fraction of the clay induces textural swelling and destructive capillary pressures during hydraulic cycles. SEM-EDS analyses reveal a heterogeneous microstructure with impurities (Fe, K) that may intensify degradation. The durability is governed by the composite microstructure rather than mineralogy alone. Cement content greater 15% is essential to ensure the long-term stability of earth-based mortars. [ABSTRACT FROM AUTHOR]
ISSN:17486025
DOI:10.1080/17486025.2025.2607015