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CITEEC is a leader in civil and building engineering research, focusing on innovative solutions for sustainable infrastructure and advanced materials.
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Pioneering research for sustainable development
CITEEC carries out pioneering research in civil engineering, materials, sustainability and infrastructure. Thanks to multidisciplinary projects and international collaborations, scientific papers are being published that address key challenges facing the sector. This section presents the main papers and results produced by our research groups.
You can access a wide range of scientific publications, which can be filtered by subject, author, year and more. Use the filters provided to find relevant literature and learn more about each of our contributions to the advancement of knowledge.
2026
Pinto-Pérez, Adonay; González-Fonteboa, Belén; Seara-Paz, Sindy; Martínez-Abella, Fernando
Assessment of mortar and paste properties in the presence of nutrients used in bacteria-based self-healing Journal Article
In: International Journal of Masonry Research and Innovation, vol. 11, no. 2, pp. 130–145, 2026, ISSN: 2056-9459.
Abstract | Links | BibTeX | Tags: calcium-lactate, calcium-nitrate, Mortar, paste, self-healing, yeast-extract
@article{pinto_assessment_2026,
title = {Assessment of mortar and paste properties in the presence of nutrients used in bacteria-based self-healing},
author = {Adonay Pinto-Pérez and Belén González-Fonteboa and Sindy Seara-Paz and Fernando Martínez-Abella},
url = {https://www.inderscienceonline.com/doi/abs/10.1504/IJMRI.2026.152244},
doi = {10.1504/IJMRI.2026.152244},
issn = {2056-9459},
year = {2026},
date = {2026-01-01},
urldate = {2026-01-01},
journal = {International Journal of Masonry Research and Innovation},
volume = {11},
number = {2},
pages = {130–145},
publisher = {Inderscience Publishers},
abstract = {Small cracks in cement-based materials represent one of their primary weak points. To address this, self-sealing techniques have emerged, being one of them the use of bacteria and nutrients. The objective of this work is to analyse the effect that these nutrients have on the properties of mortars and pastes. To achieve this, yeast extract, calcium lactate and calcium nitrate were selected. For mortar characterisation, compressive strength, and shrinkage tests were developed. These tests were complemented with rheological tests stress growth test and flow curve test in pastes. The results demonstrate how the incorporation of these nutrients alters the properties of mortars and pastes, such as the decrease of almost 50% in early age strengths when yeast extract is used at 1.25%, the significant increase in shrinkage when lactate is employed at 4% by up to 81%, or the increase in fluidity when nitrate is used, among others.},
keywords = {calcium-lactate, calcium-nitrate, Mortar, paste, self-healing, yeast-extract},
pubstate = {published},
tppubtype = {article}
}
Small cracks in cement-based materials represent one of their primary weak points. To address this, self-sealing techniques have emerged, being one of them the use of bacteria and nutrients. The objective of this work is to analyse the effect that these nutrients have on the properties of mortars and pastes. To achieve this, yeast extract, calcium lactate and calcium nitrate were selected. For mortar characterisation, compressive strength, and shrinkage tests were developed. These tests were complemented with rheological tests stress growth test and flow curve test in pastes. The results demonstrate how the incorporation of these nutrients alters the properties of mortars and pastes, such as the decrease of almost 50% in early age strengths when yeast extract is used at 1.25%, the significant increase in shrinkage when lactate is employed at 4% by up to 81%, or the increase in fluidity when nitrate is used, among others.
2023
Ghorbel, Elhem; Wardeh, George; González-Fonteboa, Belén
Effect of 10% recycled sands from various storage sites on the mortar’s properties Journal Article
In: European Journal of Environmental and Civil Engineering, vol. 27, no. 14, pp. 4067–4085, 2023, ISSN: 1964-8189.
Abstract | Links | BibTeX | Tags: Mechanical properties, Mortar, Physical properties, Recycled sand, Workability
@article{ghorbel_effect_2023,
title = {Effect of 10% recycled sands from various storage sites on the mortar’s properties},
author = {Elhem Ghorbel and George Wardeh and Belén González-Fonteboa},
url = {https://doi.org/10.1080/19648189.2023.2169766},
doi = {10.1080/19648189.2023.2169766},
issn = {1964-8189},
year = {2023},
date = {2023-10-01},
urldate = {2026-08-13},
journal = {European Journal of Environmental and Civil Engineering},
volume = {27},
number = {14},
pages = {4067–4085},
publisher = {Taylor & Francis},
abstract = {This study investigates the effects of using 10% of recycled sand in mortars. Using the concrete equivalent mortar approach, the reference mortar was developed from a flowable natural aggregate concrete with a C35/45 strength class. Five mortars were manufactured by replacing 10% of the natural sand with recycled sand from various recycling platforms while keeping the formulation parameters constant. The fresh state results showed that recycled mortar had an increased air content, which increased yield stress and viscosity. In addition, mortars containing 10% recycled sand showed a faster rate of flow loss over time. There was no difference between the materials in the hardening state with regard to the evolution of the hydration heat or the setting time. The relationship between the qualities of mortars and sands revealed that the air content depends on the sand’s fineness and the presence of fines with a diameter less than 63 µm. A relatively small increase in porosity and water absorption capacity was observed with a decrease in the compressive and flexural strength with no obvious change in the elastic modulus. The total shrinkage was revealed to depend on the fines content and decreases when the fines content increases.},
keywords = {Mechanical properties, Mortar, Physical properties, Recycled sand, Workability},
pubstate = {published},
tppubtype = {article}
}
This study investigates the effects of using 10% of recycled sand in mortars. Using the concrete equivalent mortar approach, the reference mortar was developed from a flowable natural aggregate concrete with a C35/45 strength class. Five mortars were manufactured by replacing 10% of the natural sand with recycled sand from various recycling platforms while keeping the formulation parameters constant. The fresh state results showed that recycled mortar had an increased air content, which increased yield stress and viscosity. In addition, mortars containing 10% recycled sand showed a faster rate of flow loss over time. There was no difference between the materials in the hardening state with regard to the evolution of the hydration heat or the setting time. The relationship between the qualities of mortars and sands revealed that the air content depends on the sand’s fineness and the presence of fines with a diameter less than 63 µm. A relatively small increase in porosity and water absorption capacity was observed with a decrease in the compressive and flexural strength with no obvious change in the elastic modulus. The total shrinkage was revealed to depend on the fines content and decreases when the fines content increases.
Martínez-García, Carolina; González-Fonteboa, Belén; Carro-López, Diego; Pérez-Ordóñez, Juan Luis; Martínez-Abella, Fernando
Bivalve Shells as a Building Material. A Real Case Application Journal Article
In: Lecture Notes in Civil Engineering, vol. 345, pp. 3-20, 2023, ISSN: 23662557, (cited By 0).
Abstract | Links | BibTeX | Tags: Binders; Buildings; Cements; Concrete aggregates; Energy utilization; Environmental impact; Lime; Mechanical permeability; Microstructure; Molluscs; Pore size; Shells (structures); Sustainable development; Thermal insulation, Bivalve shells; Buildings materials; Coating mortars; Concrete; Experimental buildings; Mussel shells; Partial substitution; PhD thesis; Real case; Shell by-products, Mortar
@article{Martínez-García20233,
title = {Bivalve Shells as a Building Material. A Real Case Application},
author = {Carolina Martínez-García and Belén González-Fonteboa and Diego Carro-López and Juan Luis Pérez-Ordóñez and Fernando Martínez-Abella},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85167611545&doi=10.1007%2f978-981-99-2714-2_1&partnerID=40&md5=9594c3f1bd4b18fab9b5e43aa61c3076},
doi = {10.1007/978-981-99-2714-2_1},
issn = {23662557},
year = {2023},
date = {2023-01-01},
urldate = {2023-01-01},
journal = {Lecture Notes in Civil Engineering},
volume = {345},
pages = {3-20},
publisher = {Springer Science and Business Media Deutschland GmbH},
abstract = {In a research project, Biovalvo Project, developed in the University of A Coruña, mussel shells by-products of the local canning industry were converted into a building material. The main milestone of the project was the construction of an experimental building as a real case application. This building used heat-treated and grinded mussel shells in all the building solutions: as aggregates in the foundation concretes and in the coating mortars as partial substitution for conventional aggregates. They were also used as the only thermal and acoustic insulation for the entire envelope. Derived from the project, a PhD thesis was developed where a deep analysis of the mussel shell materials was carried out. Properties of cement-based concrete were assessed including workability, mechanical strength, permeability, absorption, weight loss and microstructure. In the case of plasters and renders, mussel shells mortars were made with two binders: cement and air lime. The study included the analysis of mortars’ properties such as consistency, stiffening time, mechanical behaviour, air content, porosity, pore size distribution, microstructure, carbonation and hygric behaviour. Thermal and acoustic behaviour of mussel shells as loose fill insulation were assessed, and also their compaction and settling capacity were analysed. The potential environmental impact of the mussel shell product was performed using a cradle-to-gate approach. In the case of building solutions, the U-value calculation of the opaque elements, based on laboratory test, allowed to design an experimental building with a low energy consumption. This manuscript highlights the high potential that offers this by-product and summarizes the main results of the Biovalvo Project. © 2023, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.},
note = {cited By 0},
keywords = {Binders; Buildings; Cements; Concrete aggregates; Energy utilization; Environmental impact; Lime; Mechanical permeability; Microstructure; Molluscs; Pore size; Shells (structures); Sustainable development; Thermal insulation, Bivalve shells; Buildings materials; Coating mortars; Concrete; Experimental buildings; Mussel shells; Partial substitution; PhD thesis; Real case; Shell by-products, Mortar},
pubstate = {published},
tppubtype = {article}
}
In a research project, Biovalvo Project, developed in the University of A Coruña, mussel shells by-products of the local canning industry were converted into a building material. The main milestone of the project was the construction of an experimental building as a real case application. This building used heat-treated and grinded mussel shells in all the building solutions: as aggregates in the foundation concretes and in the coating mortars as partial substitution for conventional aggregates. They were also used as the only thermal and acoustic insulation for the entire envelope. Derived from the project, a PhD thesis was developed where a deep analysis of the mussel shell materials was carried out. Properties of cement-based concrete were assessed including workability, mechanical strength, permeability, absorption, weight loss and microstructure. In the case of plasters and renders, mussel shells mortars were made with two binders: cement and air lime. The study included the analysis of mortars’ properties such as consistency, stiffening time, mechanical behaviour, air content, porosity, pore size distribution, microstructure, carbonation and hygric behaviour. Thermal and acoustic behaviour of mussel shells as loose fill insulation were assessed, and also their compaction and settling capacity were analysed. The potential environmental impact of the mussel shell product was performed using a cradle-to-gate approach. In the case of building solutions, the U-value calculation of the opaque elements, based on laboratory test, allowed to design an experimental building with a low energy consumption. This manuscript highlights the high potential that offers this by-product and summarizes the main results of the Biovalvo Project. © 2023, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.
Martínez-García, Carolina; González-Fonteboa, Belén; Carro-López, Diego; Pérez-Ordóñez, Juan Luis; Martínez-Abella, Fernando
Bivalve Shells as a Building Material. A Real Case Application Book Section
In: Bienvenido-Huertas, David; Durán-Álvarez, Joaquín (Ed.): Building Engineering Facing the Challenges of the 21st Century: Holistic Study from the Perspectives of Materials, Construction, Energy and Sustainability, pp. 3–20, Springer Nature, Singapore, 2023, ISBN: 978-981-99-2714-2.
Abstract | Links | BibTeX | Tags: Aggregates, concrete, Mortar, Mussel shells, Sustainability, Thermal insulation
@incollection{martinez-garcia_bivalve_2023,
title = {Bivalve Shells as a Building Material. A Real Case Application},
author = {Carolina Martínez-García and Belén González-Fonteboa and Diego Carro-López and Juan Luis Pérez-Ordóñez and Fernando Martínez-Abella},
editor = {David Bienvenido-Huertas and Joaquín Durán-Álvarez},
url = {https://doi.org/10.1007/978-981-99-2714-2_1},
doi = {10.1007/978-981-99-2714-2_1},
isbn = {978-981-99-2714-2},
year = {2023},
date = {2023-01-01},
urldate = {2023-01-01},
booktitle = {Building Engineering Facing the Challenges of the 21st Century: Holistic Study from the Perspectives of Materials, Construction, Energy and Sustainability},
pages = {3–20},
publisher = {Springer Nature},
address = {Singapore},
abstract = {In a research project, Biovalvo Project, developed in the University of A Coruña, mussel shells by-products of the local canning industry were converted into a building material. The main milestone of the project was the construction of an experimental building as a real case application. This building used heat-treated and grinded mussel shells in all the building solutions: as aggregates in the foundation concretes and in the coating mortars as partial substitution for conventional aggregates. They were also used as the only thermal and acoustic insulation for the entire envelope. Derived from the project, a PhD thesis was developed where a deep analysis of the mussel shell materials was carried out. Properties of cement-based concrete were assessed including workability, mechanical strength, permeability, absorption, weight loss and microstructure. In the case of plasters and renders, mussel shells mortars were made with two binders: cement and air lime. The study included the analysis of mortars’ properties such as consistency, stiffening time, mechanical behaviour, air content, porosity, pore size distribution, microstructure, carbonation and hygric behaviour. Thermal and acoustic behaviour of mussel shells as loose fill insulation were assessed, and also their compaction and settling capacity were analysed. The potential environmental impact of the mussel shell product was performed using a cradle-to-gate approach. In the case of building solutions, the U-value calculation of the opaque elements, based on laboratory test, allowed to design an experimental building with a low energy consumption. This manuscript highlights the high potential that offers this by-product and summarizes the main results of the Biovalvo Project.},
keywords = {Aggregates, concrete, Mortar, Mussel shells, Sustainability, Thermal insulation},
pubstate = {published},
tppubtype = {incollection}
}
In a research project, Biovalvo Project, developed in the University of A Coruña, mussel shells by-products of the local canning industry were converted into a building material. The main milestone of the project was the construction of an experimental building as a real case application. This building used heat-treated and grinded mussel shells in all the building solutions: as aggregates in the foundation concretes and in the coating mortars as partial substitution for conventional aggregates. They were also used as the only thermal and acoustic insulation for the entire envelope. Derived from the project, a PhD thesis was developed where a deep analysis of the mussel shell materials was carried out. Properties of cement-based concrete were assessed including workability, mechanical strength, permeability, absorption, weight loss and microstructure. In the case of plasters and renders, mussel shells mortars were made with two binders: cement and air lime. The study included the analysis of mortars’ properties such as consistency, stiffening time, mechanical behaviour, air content, porosity, pore size distribution, microstructure, carbonation and hygric behaviour. Thermal and acoustic behaviour of mussel shells as loose fill insulation were assessed, and also their compaction and settling capacity were analysed. The potential environmental impact of the mussel shell product was performed using a cradle-to-gate approach. In the case of building solutions, the U-value calculation of the opaque elements, based on laboratory test, allowed to design an experimental building with a low energy consumption. This manuscript highlights the high potential that offers this by-product and summarizes the main results of the Biovalvo Project.
2020
Martínez-García, Carolina; González-Fonteboa, Belén; Carro-López, Diego; Martínez-Abella, Fernando
Effects of mussel shell aggregates on hygric behaviour of air lime mortar at different ages Journal Article
In: Construction and Building Materials, vol. 252, 2020, ISSN: 09500618, (cited By 16).
Abstract | Links | BibTeX | Tags: Aggregates; Biogeochemistry; Calcium carbonate; Lime; Molluscs; Organic compounds; Shells (structures); Water absorption, Different ages; Lime mortars; Mussel shells; Organic matter content; Resistance index; Substitution rates; Sustainable construction; Water retention, Mortar
@article{Martínez-García2020,
title = {Effects of mussel shell aggregates on hygric behaviour of air lime mortar at different ages},
author = {Carolina Martínez-García and Belén González-Fonteboa and Diego Carro-López and Fernando Martínez-Abella},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85083107017&doi=10.1016%2fj.conbuildmat.2020.119113&partnerID=40&md5=f571694cb83b0e3279790c3b0e16acb6},
doi = {10.1016/j.conbuildmat.2020.119113},
issn = {09500618},
year = {2020},
date = {2020-01-01},
urldate = {2020-01-01},
journal = {Construction and Building Materials},
volume = {252},
publisher = {Elsevier Ltd},
abstract = {Mussel shells, composed of calcium carbonate (>95%) and organic matter, are suitable alternatives to conventional sand in mortar. In addition, the use of lime instead of cement as a binder has also been considered for sustainable construction materials as well as in restorative applications. This study aims to contribute to the knowledge of air lime mortar through the analysis of the water transport properties of air lime mortar produced with mussel shell aggregates at different ages. Four mortar groups were obtained from the reference mortar by replacing limestone sand with mussel shell sand at substitution rates of 25%, 50%, and 75%. Water absorption, capillary uptake, weight variation, and drying from the fresh state up till one and two years were determined. The organic matter content and flaky seashell shape are responsible for the main differences observed between the mussel mortars and reference mortar. These two characteristics promote transport tortuosity paths and hydrophobic behaviour leading to reduced capillary uptake and increased drying resistance index. Furthermore, they enhance water retention, which increases the carbonation rate. © 2020 Elsevier Ltd},
note = {cited By 16},
keywords = {Aggregates; Biogeochemistry; Calcium carbonate; Lime; Molluscs; Organic compounds; Shells (structures); Water absorption, Different ages; Lime mortars; Mussel shells; Organic matter content; Resistance index; Substitution rates; Sustainable construction; Water retention, Mortar},
pubstate = {published},
tppubtype = {article}
}
Mussel shells, composed of calcium carbonate (>95%) and organic matter, are suitable alternatives to conventional sand in mortar. In addition, the use of lime instead of cement as a binder has also been considered for sustainable construction materials as well as in restorative applications. This study aims to contribute to the knowledge of air lime mortar through the analysis of the water transport properties of air lime mortar produced with mussel shell aggregates at different ages. Four mortar groups were obtained from the reference mortar by replacing limestone sand with mussel shell sand at substitution rates of 25%, 50%, and 75%. Water absorption, capillary uptake, weight variation, and drying from the fresh state up till one and two years were determined. The organic matter content and flaky seashell shape are responsible for the main differences observed between the mussel mortars and reference mortar. These two characteristics promote transport tortuosity paths and hydrophobic behaviour leading to reduced capillary uptake and increased drying resistance index. Furthermore, they enhance water retention, which increases the carbonation rate. © 2020 Elsevier Ltd
Rojo-López, Gemma; Nunes, Sandra; González-Fonteboa, Belén; Martínez-Abella, Fernando
Quaternary blends of portland cement, metakaolin, biomass ash and granite powder for production of self-compacting concrete Journal Article
In: Journal of Cleaner Production, vol. 266, 2020, (Cited by: 47; All Open Access, Green Open Access).
Abstract | Links | BibTeX | Tags: Binary mixtures, Carbon dioxide, Cement industry, Circular economy, Compressive strength, Concrete industry, Concrete mixtures, Concrete products, Cost engineering, Designed experiments, Efficiency, Engineering properties, Industrial emissions, Industrial sector, Material efficiency, Mortar, Portland cement, Resource efficiencies, Self compacting concrete, Supplementary cementitious material, Sustainable waste management, Waste management
@article{Rojo-López2020,
title = {Quaternary blends of portland cement, metakaolin, biomass ash and granite powder for production of self-compacting concrete},
author = {Gemma Rojo-López and Sandra Nunes and Belén González-Fonteboa and Fernando Martínez-Abella},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85084552139&doi=10.1016%2fj.jclepro.2020.121666&partnerID=40&md5=432f2c1cfd49358288f98b4f03788f9d},
doi = {10.1016/j.jclepro.2020.121666},
year = {2020},
date = {2020-01-01},
urldate = {2020-01-01},
journal = {Journal of Cleaner Production},
volume = {266},
publisher = {Elsevier Ltd},
abstract = {Given the rising societal pressure towards sustainable waste management and resource efficiency, in a more circular economy, an increased use and diversification of supplementary cementitious materials (SCM) will be necessary to achieve the CO2 mitigation goals. The current study addresses the development of self-compacting concrete, replacing part of the cement (the primary source of CO2 emissions) by metakaolin and wastes derived from two industrial sectors operating in the “Galicia–North of Portugal Euroregion”: wood manufacturing and natural stone quarrying. A study was carried out at the mortar level to investigate the effect of the mix design variables on several engineering properties of the self-compacting concrete. Statistically designed experiments reveal that an increase in water/powder volume ratio has a dominant effect on the fresh state properties, whereas the water/cement weight ratio has a dominant effect on the hardened state properties. A like-for-like comparison of the proposed quaternary blends and previously studied binary/ternary blends indicates that these mixtures exhibit improved self-compacting ability, greater compressive strength, and can offer interesting opportunities to reduce the unit cost and environmental impact of self-compacting concrete per m3. Four different mortar mixtures were optimised to achieve excellent self-compacting ability yet with distinct compressive strength levels at 28 days (65, 70, 75, and 80 MPa). A single measure of the material efficiency is proposed herein to reflect the engineering properties improvement (workability, compressive strength, and durability) over its economic (unit cost) and environmental impact. © 2020 Elsevier Ltd},
note = {Cited by: 47; All Open Access, Green Open Access},
keywords = {Binary mixtures, Carbon dioxide, Cement industry, Circular economy, Compressive strength, Concrete industry, Concrete mixtures, Concrete products, Cost engineering, Designed experiments, Efficiency, Engineering properties, Industrial emissions, Industrial sector, Material efficiency, Mortar, Portland cement, Resource efficiencies, Self compacting concrete, Supplementary cementitious material, Sustainable waste management, Waste management},
pubstate = {published},
tppubtype = {article}
}
Given the rising societal pressure towards sustainable waste management and resource efficiency, in a more circular economy, an increased use and diversification of supplementary cementitious materials (SCM) will be necessary to achieve the CO2 mitigation goals. The current study addresses the development of self-compacting concrete, replacing part of the cement (the primary source of CO2 emissions) by metakaolin and wastes derived from two industrial sectors operating in the “Galicia–North of Portugal Euroregion”: wood manufacturing and natural stone quarrying. A study was carried out at the mortar level to investigate the effect of the mix design variables on several engineering properties of the self-compacting concrete. Statistically designed experiments reveal that an increase in water/powder volume ratio has a dominant effect on the fresh state properties, whereas the water/cement weight ratio has a dominant effect on the hardened state properties. A like-for-like comparison of the proposed quaternary blends and previously studied binary/ternary blends indicates that these mixtures exhibit improved self-compacting ability, greater compressive strength, and can offer interesting opportunities to reduce the unit cost and environmental impact of self-compacting concrete per m3. Four different mortar mixtures were optimised to achieve excellent self-compacting ability yet with distinct compressive strength levels at 28 days (65, 70, 75, and 80 MPa). A single measure of the material efficiency is proposed herein to reflect the engineering properties improvement (workability, compressive strength, and durability) over its economic (unit cost) and environmental impact. © 2020 Elsevier Ltd
2019
Francioso, Vito; Moro, Carlos; Martínez-Lage, Isabel; Velay-Lizancos, Mirian
In: Cement and Concrete Composites, vol. 104, pp. 103374, 2019, ISSN: 0958-9465.
Abstract | Links | BibTeX | Tags: Calcium hydroxide, Curing temperature, Mortar, Pore structure, Strength, Titanium dioxide nanoparticles
@article{francioso_curing_2019,
title = {Curing temperature: A key factor that changes the effect of TiO2 nanoparticles on mechanical properties, calcium hydroxide formation and pore structure of cement mortars},
author = {Vito Francioso and Carlos Moro and Isabel Martínez-Lage and Mirian Velay-Lizancos},
url = {https://www.sciencedirect.com/science/article/pii/S0958946519304494},
doi = {10.1016/j.cemconcomp.2019.103374},
issn = {0958-9465},
year = {2019},
date = {2019-11-01},
urldate = {2026-08-06},
journal = {Cement and Concrete Composites},
volume = {104},
pages = {103374},
abstract = {There are several studies about the effects of addition of TiO2 nanoparticles in mortar properties, but they were made at a given temperature. However, are the effects of this addition independent of curing temperature? The present research focused on the influence of TiO2 nanoparticles at three curing temperatures: 5 °C, 20 °C and 45 °C. Four different mortar mixtures were investigated: a reference mortar (without nanomaterial) and three mortars with different percentages of TiO2 (0.25%, 0.5% and 1%) by the total amount of cement for the reference mortar. For each curing temperature, the effect of TiO2 on (i) compressive and flexural strength at 7 days, (ii) calcium hydroxide (CH) formation at 1, 3 at 7 days and (iii) pore structure have been studied. The effect of TiO2 on compressive and flexural strength depends strongly on curing temperature: the higher the curing temperature, the lower the positive effect of TiO2. If this fact is not considered when curing temperature is higher than the standard (20 °C), improvements due to TiO2 substitution would not be as considerable as it is expected. TiO2 promotes CH carbonation during sample preparation. Results suggest that promotion of hydration is not the only effect of TiO2, which can contribute to enhance strength. A potential mechanism of these nanoparticles to enhance strength could be the modification of pore structure; according to 3D X-Ray microscope results, at 20 °C, TiO2 makes pores smaller, more homogeneous and spherical.},
keywords = {Calcium hydroxide, Curing temperature, Mortar, Pore structure, Strength, Titanium dioxide nanoparticles},
pubstate = {published},
tppubtype = {article}
}
There are several studies about the effects of addition of TiO2 nanoparticles in mortar properties, but they were made at a given temperature. However, are the effects of this addition independent of curing temperature? The present research focused on the influence of TiO2 nanoparticles at three curing temperatures: 5 °C, 20 °C and 45 °C. Four different mortar mixtures were investigated: a reference mortar (without nanomaterial) and three mortars with different percentages of TiO2 (0.25%, 0.5% and 1%) by the total amount of cement for the reference mortar. For each curing temperature, the effect of TiO2 on (i) compressive and flexural strength at 7 days, (ii) calcium hydroxide (CH) formation at 1, 3 at 7 days and (iii) pore structure have been studied. The effect of TiO2 on compressive and flexural strength depends strongly on curing temperature: the higher the curing temperature, the lower the positive effect of TiO2. If this fact is not considered when curing temperature is higher than the standard (20 °C), improvements due to TiO2 substitution would not be as considerable as it is expected. TiO2 promotes CH carbonation during sample preparation. Results suggest that promotion of hydration is not the only effect of TiO2, which can contribute to enhance strength. A potential mechanism of these nanoparticles to enhance strength could be the modification of pore structure; according to 3D X-Ray microscope results, at 20 °C, TiO2 makes pores smaller, more homogeneous and spherical.
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