Clay-gypsum mortars: The influence of binder and sand ratios

Douglas Rocha; Paulina Faria; Sandra S. Lucas

doi:10.1016/j.rineng.2025.104702

Clay-gypsum mortars: The influence of binder and sand ratios

Douglas Rocha (Corresponding author), Paulina Faria, Sandra S. Lucas

Research output: Contribution to journal › Article › Academic › peer-review

1 Citation (Scopus)

10 Downloads (Pure)

Abstract

Prefabricating building elements minimizes material waste and enhances quality control. This study proposes a new formulation of clay-based mortars foreseen to produce prefabricated coating panels. The effect of the binder:sand ratio (1:2, 1:3 and 1:4, in volume) and clay replacement by gypsum (5%, 10% and 20% in volume) is assessed. The investigation focused on key properties, including workability, flow table consistence, setting time of the fresh mortars, linear shrinkage, bulk density, and flexural and compressive strengths of the hardened mortars. The clay content demonstrates a proportional impact on dimensional variation, with linear shrinkage exceeding 2% in mortars with high clay content. Gypsum partial substitution has a small effect on fresh mortar properties, but it significantly reduces setting time and enhances mechanical performance. In mortars with different sand contents, replacing clay by 20% gypsum increases compressive strength by 320% and flexural strength by 685%. Therefore, these optimized clay-gypsum mortars seem to have the potential for producing environmentally friendly prefabricated coating panels.

Original language	English
Article number	104702
Number of pages	13
Journal	Results in Engineering
Volume	26
Early online date	30 Mar 2025
DOIs	https://doi.org/10.1016/j.rineng.2025.104702
Publication status	Published - Jun 2025

Funding

The authors would like to acknowledge the support provided by Eindhoven University of Technology during the period of guest research. The authors are grateful to Winnie Franco Santos for her support during the preparation of this article. Acknowledgments are also due to the Erasmus+ project BIO-FIBRE (KA220-HED-2022-003). This research was funded by the Portuguese Foundation for Science and Technology (FCT) (Douglas Rocha's PhD grant 2021.05371.BD, DOI:10.54499/2021.05371.BD), and UIDB/04625/2020 (Civil Engineering Research and Innovation for Sustainability Unit\u2014CERIS, DOI: 10.54499/UIDB/04625/2020).

Funders	Funder number
Portuguese Fundação para a Ciência e a Tecnologia	2021.05371.BD, DOI:10.54499/2021.05371.BD

Keywords

Calcium sulfate hemihydrate
Clayish earth
Earth as building material
Eco-efficient mortar

Access to Document

10.1016/j.rineng.2025.104702

pdfFinal published version, 3.46 MBLicence: CC BY

Cite this

@article{2beccd28c6cc408c874e1b9342525fda,

title = "Clay-gypsum mortars: The influence of binder and sand ratios",

abstract = "Prefabricating building elements minimizes material waste and enhances quality control. This study proposes a new formulation of clay-based mortars foreseen to produce prefabricated coating panels. The effect of the binder:sand ratio (1:2, 1:3 and 1:4, in volume) and clay replacement by gypsum (5%, 10% and 20% in volume) is assessed. The investigation focused on key properties, including workability, flow table consistence, setting time of the fresh mortars, linear shrinkage, bulk density, and flexural and compressive strengths of the hardened mortars. The clay content demonstrates a proportional impact on dimensional variation, with linear shrinkage exceeding 2% in mortars with high clay content. Gypsum partial substitution has a small effect on fresh mortar properties, but it significantly reduces setting time and enhances mechanical performance. In mortars with different sand contents, replacing clay by 20% gypsum increases compressive strength by 320% and flexural strength by 685%. Therefore, these optimized clay-gypsum mortars seem to have the potential for producing environmentally friendly prefabricated coating panels.",

keywords = "Calcium sulfate hemihydrate, Clayish earth, Earth as building material, Eco-efficient mortar",

author = "Douglas Rocha and Paulina Faria and Lucas, {Sandra S.}",

year = "2025",

month = jun,

doi = "10.1016/j.rineng.2025.104702",

language = "English",

volume = "26",

journal = "Results in Engineering",

issn = "2590-1230",

publisher = "Elsevier",

}

TY - JOUR

T1 - Clay-gypsum mortars

T2 - The influence of binder and sand ratios

AU - Rocha, Douglas

AU - Faria, Paulina

AU - Lucas, Sandra S.

PY - 2025/6

Y1 - 2025/6

N2 - Prefabricating building elements minimizes material waste and enhances quality control. This study proposes a new formulation of clay-based mortars foreseen to produce prefabricated coating panels. The effect of the binder:sand ratio (1:2, 1:3 and 1:4, in volume) and clay replacement by gypsum (5%, 10% and 20% in volume) is assessed. The investigation focused on key properties, including workability, flow table consistence, setting time of the fresh mortars, linear shrinkage, bulk density, and flexural and compressive strengths of the hardened mortars. The clay content demonstrates a proportional impact on dimensional variation, with linear shrinkage exceeding 2% in mortars with high clay content. Gypsum partial substitution has a small effect on fresh mortar properties, but it significantly reduces setting time and enhances mechanical performance. In mortars with different sand contents, replacing clay by 20% gypsum increases compressive strength by 320% and flexural strength by 685%. Therefore, these optimized clay-gypsum mortars seem to have the potential for producing environmentally friendly prefabricated coating panels.

AB - Prefabricating building elements minimizes material waste and enhances quality control. This study proposes a new formulation of clay-based mortars foreseen to produce prefabricated coating panels. The effect of the binder:sand ratio (1:2, 1:3 and 1:4, in volume) and clay replacement by gypsum (5%, 10% and 20% in volume) is assessed. The investigation focused on key properties, including workability, flow table consistence, setting time of the fresh mortars, linear shrinkage, bulk density, and flexural and compressive strengths of the hardened mortars. The clay content demonstrates a proportional impact on dimensional variation, with linear shrinkage exceeding 2% in mortars with high clay content. Gypsum partial substitution has a small effect on fresh mortar properties, but it significantly reduces setting time and enhances mechanical performance. In mortars with different sand contents, replacing clay by 20% gypsum increases compressive strength by 320% and flexural strength by 685%. Therefore, these optimized clay-gypsum mortars seem to have the potential for producing environmentally friendly prefabricated coating panels.

KW - Calcium sulfate hemihydrate

KW - Clayish earth

KW - Earth as building material

KW - Eco-efficient mortar

UR - http://www.scopus.com/inward/record.url?scp=105001727602&partnerID=8YFLogxK

U2 - 10.1016/j.rineng.2025.104702

DO - 10.1016/j.rineng.2025.104702

M3 - Article

SN - 2590-1230

VL - 26

JO - Results in Engineering

JF - Results in Engineering

M1 - 104702

ER -

Clay-gypsum mortars: The influence of binder and sand ratios

Abstract

Funding

Keywords

Access to Document

Other files and links

Fingerprint

Cite this