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Low Portland cement content concretes at freezing and subfreezing temperatures
Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.ORCID iD: 0000-0001-5136-9412
2024 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Concrete is the most used building material. With the increasing growth of industries and urbanization globally; the demand for concrete is increasing significantly. Ordinary Portland Cement (PC) is the binder used to produce typical concrete. Unfortunately, for every ton of manufactured cement about 0.61-ton CO2 is emitted into the earth’s atmosphere. As a result, several solutions have been implemented to reduce the usage of this material in the production of concrete. This includes its partial or full replacement with supplementary cementitious materials (SCMs) or alternative binders. Some of these combinations could be problematic to be used in cold climates due to a lower developed hydration heat, slower setting, or worse frost durability.

In winter the immediate exposure of fresh concrete to freezing temperatures results in pore ice formation and could delay or completely stop the hydration process. This is commonly prevented by using an additional heating system installed in concrete or the formwork. Unfortunately, usually, it adds complexity, increases the price, and depending on the used power source, could increase the CO2 footprint. Another potentially simpler and more sustainable solution is to modify the concrete itself by adjusting the mix design, by using certain chemical admixtures and special cementitious binders.

This research aimed to better understand how partial replacement of Portland cement with GGBFS and/or CSA cement affects the properties of concretes exposed to freezing and subfreezing temperatures in a fresh state and at a young age. The secondary aim was to evaluate a possible application of UHPC to protect new and existing concrete structures from frost damage.

The research included a literature review of methods used to produce concrete structures at zero and subzero temperatures. A special emphasis was on the application of chemical and mineral admixtures that could eliminate the need to use heat treatments. The output of this analysis enabled to narrow the scope of the research.

The experimental program focused on the optimization, testing, and analysis of mixes containing various combinations of chemical admixtures, CSA cement, and Portland cement. Tests included exposure to freezing and subfreezing temperatures. The aim was to lower the freezing point of water and promote faster hydration and strength gain. Fresh and hardened properties were determined for all produced concretes. The phase transition of pore water into ice, the ice-forming temperature, and their effects on the binder matrix were studied using differential scanning calorimetry (DSC). Other tests included ultrasonic pulse velocity measurements (UPV), bond test (pull-off), scanning electron microscope (SEM) for analysis of the microstructure and phase composition, frost durability evaluation with Båras test, semi-adiabatic calorimetry to study hydration processes, compressive strength measurements.

Place, publisher, year, edition, pages
Luleå: Luleå University of Technology, 2024.
Series
Doctoral thesis / Luleå University of Technology 1 jan 1997 → …, ISSN 1402-1544
National Category
Building Technologies Composite Science and Engineering
Research subject
Building Materials
Identifiers
URN: urn:nbn:se:ltu:diva-105133ISBN: 978-91-8048-540-1 (print)ISBN: 978-91-8048-541-8 (electronic)OAI: oai:DiVA.org:ltu-105133DiVA, id: diva2:1852091
Public defence
2024-06-18, F1031, Luleå University of Technology, Luleå, 10:00 (English)
Opponent
Supervisors
Funder
InterregVinnovaSvenska Byggbranschens Utvecklingsfond (SBUF)Swedish Transport AdministrationSwedish Energy AgencyAvailable from: 2024-04-17 Created: 2024-04-16 Last updated: 2024-05-28Bibliographically approved
List of papers
1. A Review of the Mechanical Properties and Durability of Ecological Concretes in a Cold Climate in Comparison to Standard Ordinary Portland Cement-Based Concrete
Open this publication in new window or tab >>A Review of the Mechanical Properties and Durability of Ecological Concretes in a Cold Climate in Comparison to Standard Ordinary Portland Cement-Based Concrete
2020 (English)In: Materials, ISSN 1996-1944, E-ISSN 1996-1944, Vol. 13, no 16, article id 3467Article, review/survey (Refereed) Published
Abstract [en]

Most of the currently used concretes are based on ordinary Portland cement (OPC) which results in a high carbon dioxide footprint and thus has a negative environmental impact. Replacing OPCs, partially or fully by ecological binders, i.e., supplementary cementitious materials (SCMs) or alternative binders, aims to decrease the carbon dioxide footprint. Both solutions introduced a number of technological problems, including their performance, when exposed to low, subfreezing temperatures during casting operations and the hardening stage. This review indicates that the present knowledge enables the production of OPC-based concretes at temperatures as low as −10 °C, without the need of any additional measures such as, e.g., heating. Conversely, composite cements containing SCMs or alkali-activated binders (AACs) showed mixed performances, ranging from inferior to superior in comparison with OPC. Most concretes based on composite cements require pre/post heat curing or only a short exposure to sub-zero temperatures. At the same time, certain alkali-activated systems performed very well even at −20 °C without the need for additional curing. Chemical admixtures developed for OPC do not always perform well in other binder systems. This review showed that there is only a limited knowledge on how chemical admixtures work in ecological concretes at low temperatures and how to accelerate the hydration rate of composite cements containing high amounts of SCMs or AACs, when these are cured at subfreezing temperatures.

Place, publisher, year, edition, pages
Basel, Switzerland: MDPI, 2020
Keywords
ordinary Portland cement (OPC), supplementary cementitious materials (SCM), alkali-activated concrete (AAC), chemical admixtures, sustainable concrete, mechanical properties, frost durability
National Category
Other Materials Engineering
Research subject
Building Materials
Identifiers
urn:nbn:se:ltu:diva-80353 (URN)10.3390/ma13163467 (DOI)000564883200001 ()32781636 (PubMedID)2-s2.0-85090027318 (Scopus ID)
Funder
Interreg Nord, NYPS 20201459Norrbotten County Council
Note

Validerad;2020;Nivå 2;2020-08-17 (alebob)

Available from: 2020-08-11 Created: 2020-08-11 Last updated: 2024-04-16Bibliographically approved
2. Effects of sodium nitrate and OPC-GGBS concrete mix composition on phase transition of pore water at subzero temperatures
Open this publication in new window or tab >>Effects of sodium nitrate and OPC-GGBS concrete mix composition on phase transition of pore water at subzero temperatures
2022 (English)In: Construction and Building Materials, ISSN 0950-0618, E-ISSN 1879-0526, Vol. 327, article id 126901Article in journal (Refereed) Published
Abstract [en]

Lowering the freezing temperature of the mixing water is crucial for concrete works at subzero temperatures. In this study, formation of ice was examined for various pastes and concretes of OPC-GGBS based, while exposed to a constant temperature of −15 °C. Sodium nitrate antifreeze admixture was added as 0, 6, 10, 15, 20, 25, 30 wt% by the total binder amount. The ice formation and its effects on the binder matrix microstructure was studied using differential scanning calorimetry (DSC), ultrasonic pulse velocity (UPV) and Scanning Electron Microscopy – Energy Dispersive Spectrometry (SEM-EDS). Several curing procedures were applied to samples before commencing tests. Results showed that, addition of 25 wt% of the sodium nitrate caused the most extensive delay of the ice growth. Mixes containing less admixture showed an increasing amount of the forming ice which in some cases lead to the development of the false strength. The hydration rate has been the highest for the mix with 25 wt% of the sodium nitrate and tended to be limited at lower additions. The porosity of the hydrated binder matrix tended to be lower for mixes characterized by a lower amount of the forming ice. In general, application of above freezing temperature resulted in resuming of the hydration process that led to densification of the microstructure and strength increase. This trend was more pronounced for mixes having lower amounts of the formed ice.

Place, publisher, year, edition, pages
Elsevier, 2022
Keywords
Antifreeze admixture (AF), Compressive strength, Differential scanning calorimetry (DSC), Ground Granulated Blast-Furnace Slag (GGBS), Ordinary Portland Cement (OPC), Porosity, SEM-EDS, Temperature, UPV
National Category
Other Materials Engineering
Research subject
Building Materials
Identifiers
urn:nbn:se:ltu:diva-89435 (URN)10.1016/j.conbuildmat.2022.126901 (DOI)000770575300003 ()2-s2.0-85125521821 (Scopus ID)
Projects
ARCTIC-ecocrete
Funder
Interreg NordNorrbotten County Council
Note

Validerad;2022;Nivå 2;2022-03-03 (sofila)

Available from: 2022-03-03 Created: 2022-03-03 Last updated: 2024-04-16Bibliographically approved
3. Partial replacement of OPC with CSA cements – effects on hydration, fresh-, hardened-properties
Open this publication in new window or tab >>Partial replacement of OPC with CSA cements – effects on hydration, fresh-, hardened-properties
Show others...
2023 (English)In: Advances in Cement Research, ISSN 0951-7197, E-ISSN 1751-7605, Vol. 35, no 5, p. 207-224Article in journal (Refereed) Published
Abstract [en]

The effects of a partial replacement of Ordinary Portland cement (OPC) with three types of calcium sulfoaluminate (CSA) cements (40 wt% and 20 wt%) were investigated. The obtained results were generally in agreement with previously published data but with few interesting exceptions. Setting times were shortened due to the formation of ettringite. The maximum hydration temperature increased for concretes containing 40 wt% of CSA but decreased when 20 wt% replacement was used. The decrease was related to the deficiency of the available sulfates, which limited the formation of ettringite. The presence of extra anhydrite and calcium oxide was associated to the delayed establishment of the second temperature peak in contrast to OPC-based concretes. Their surplus delayed calcium aluminate and belite reactions, and triggered renewed formation of ettringite, C-S-H and portlandite. Effects of aluminum hydroxide were also indicated as possibly important, although not proved experimentally in this research. The slightly lower compressive strength measured for mixes containing 40 wt% of CSA were linked with more formed ettringite. The same factor was indicated as the key to the reduction of the total shrinkage in mixes containing 40 wt% of CSA and increased for the lower CSA replacement level. In that case, the insufficient amount of formed ettringite caused too small expansion, which could not efficiently mitigate or compensate the developed shrinkage.

Place, publisher, year, edition, pages
ICE Publishing, 2023
Keywords
Calcium sulfoaluminate cement (CSA), Hydration, Microstructure-SEM-EDS, Ordinary Portland cement (OPC), Shrinkage, XRD
National Category
Other Materials Engineering
Research subject
Building Materials
Identifiers
urn:nbn:se:ltu:diva-93760 (URN)10.1680/jadcr.22.00054 (DOI)000880071500001 ()2-s2.0-85140233648 (Scopus ID)
Funder
Svenska Byggbranschens Utvecklingsfond (SBUF)Rock Engineering Research Foundation (BeFo)
Note

Validerad;2023;Nivå 2;2023-06-29 (joosat);

Available from: 2022-11-01 Created: 2022-11-01 Last updated: 2024-04-16Bibliographically approved
4. Early Age Performance of OPC-GGBFS-Concretes Containing Belite-CSA Cement Cured at Sub-Zero Temperatures
Open this publication in new window or tab >>Early Age Performance of OPC-GGBFS-Concretes Containing Belite-CSA Cement Cured at Sub-Zero Temperatures
2023 (English)In: Buildings, E-ISSN 2075-5309, Vol. 13, no 9, article id 2374Article in journal (Refereed) Published
Abstract [en]

This study determined how replacing sodium nitrate-based antifreeze admixture (AF) with belite-calcium sulfoaluminate (belite-CSA) cement affects the early age properties of ecological concretes based on ordinary Portland cement (OPC) and ground granulated blast-furnace slag (GGBFS). Concrete specimens were cured at −15 °C and treated in various ways before testing, i.e., no treatment, stored at 20 °C for 12 and 24 h. Generally, the addition of belite-CSA cement shortened the setting time due to the rapid formation of ettringite. The incorporation of 25 wt% of antifreeze admixture (AF) to the OPC-GGBFS concrete cured at −15 °C partially inhibited ice formation and enabled the continuation of hydration processes. This trend was observed for all samples, independent of the applied AF after freezing curing. On the contrary, the addition of 20 wt% of CSA failed to inhibit the ice formation and increased the risk of frost damage for concretes despite the treatment after freezing. These concrete specimens had lower hydration, lower strength, and a more porous binder matrix. The microstructure of the binder matrix was significantly affected by the amount of CSA and extreme negative curing, followed by no notable recovery post-curing at room temperature. Therefore, pre-curing at room temperature for at least 6 h has the potential to avoid frost damage. Concrete containing 25 wt% AF combined with 12 h and 24 h of curing at 20 °C after removal from freezing and prior to testing could enhance the compressive strengths of all concretes. The renewed hydration was indicated as the main influencing factor.

Place, publisher, year, edition, pages
MDPI, 2023
Keywords
ordinary Portland cement (OPC), calcium sulfoaluminate cement (CSA), ground granulated blast-furnace slag (GGBFS), hydration, microstructure—SEM, antifreeze admixture (AF), differential scanning calorimetry (DSC), negative temperature, compressive strength, porosity, UPV
National Category
Building Technologies Other Materials Engineering
Research subject
Building Materials
Identifiers
urn:nbn:se:ltu:diva-101403 (URN)10.3390/buildings13092374 (DOI)2-s2.0-85172798992 (Scopus ID)
Funder
Svenska Byggbranschens Utvecklingsfond (SBUF)Rock Engineering Research Foundation (BeFo)
Note

Validerad;2023;Nivå 2;2023-09-25 (hanlid)

Available from: 2023-09-21 Created: 2023-09-21 Last updated: 2024-04-16Bibliographically approved
5. Eco-UHPC as Repair Material-Bond Strength, Interfacial Transition Zone and Effects of Formwork Type
Open this publication in new window or tab >>Eco-UHPC as Repair Material-Bond Strength, Interfacial Transition Zone and Effects of Formwork Type
Show others...
2020 (English)In: Materials, ISSN 1996-1944, E-ISSN 1996-1944, Vol. 13, no 24, article id 5778Article in journal (Refereed) Published
Abstract [en]

A reduced carbon footprint and longer service life of structures are major aspects of circular economy with respect to civil engineering. The aim of the research was to evaluate the interfacial bond properties between a deteriorated normal strength concrete structure and a thin overlay made of Eco-UHPC containing 50 wt% of limestone filler. Two types of formwork were used: untreated rough plywood and surface treated shuttering plywood. The normal strength concrete elements were surface scaled using water jets to obtain some degradation prior to casting of the UHPC overlay. Ultrasonic pulse velocity (UPV), bond test (pull-off test), and Scanning Electron Microscopy (SEM) combined with Energy Dispersive Spectrometry (EDS) were used for analysis. Elements repaired with the Eco-UHPC showed significantly improved mechanical properties compared to the non-deteriorated NSC sample which was used as a reference. The bond strength varied between 2 and 2.7 MPa regardless of the used formwork. The interfacial transition zone was very narrow with only slightly increased porosity. The untreated plywood, having a rough and water-absorbing surface, created a surface friction-based restraint which limited microcracking due to autogenous shrinkage. Shuttering plywood with a smooth surface enabled the development of higher tensile stress on the UHPC surface, which led to a more intensive autogenous shrinkage cracking. None of the formed microcracks penetrated through the entire thickness of the overlay and some were partly self-healed when a simple water treatment was applied. The project results showed that application of UHPC as repair material for concrete structures could elongate the lifespan and thus enhance the sustainability.

Place, publisher, year, edition, pages
MDPI, 2020
Keywords
Eco-UHPC, NSC (normal strength concrete), UPV, bond test (pull-off), SEM-EDS, ITZ, formwork, self-healing
National Category
Other Materials Engineering
Research subject
Building Materials
Identifiers
urn:nbn:se:ltu:diva-82205 (URN)10.3390/ma13245778 (DOI)000602864400001 ()33348899 (PubMedID)2-s2.0-85098280741 (Scopus ID)
Funder
Swedish Transport AdministrationVinnova
Note

Validerad;2021;Nivå 2;2021-01-08 (johcin)

Available from: 2021-01-08 Created: 2021-01-08 Last updated: 2024-04-16Bibliographically approved
6. UHPC overlay as sustainable solution to preserve old concrete structures
Open this publication in new window or tab >>UHPC overlay as sustainable solution to preserve old concrete structures
2022 (English)In: MATEC Web of Conferences: International Conference on Concrete Repair, Rehabilitation and Retrofitting (ICCRRR 2022) / [ed] M.G. Alexander; H. Beushausen; F. Dehn; J. Ndawula; P. Moyo, EDP Sciences, 2022, article id 04014Conference paper, Published paper (Refereed)
Abstract [en]

Concrete structures exposed to harsh environments, especially including bridges, harbor structures are often suffered from durability problems. Typical external signs include surface deterioration, cracking caused by for example sulphate attack, frost action or reinforcement corrosion. All are strongly linked to the porous microstructure of the binder matrix and chemical decomposition of certain phases. Full replacement of deteriorated concrete structures is costly and can be troublesome for their users. The increasing demand to reduce the carbon footprint and to prolong the service life of concrete structures adds yet another argument to restore the existing structures. One alternative is to use very dense Ultra-High-Performance concrete (UHPC) as an external protective coating. The goal of this study was to determine the interfacial bonding characteristics between a damaged normal concrete (NC) and the applied thin layer of the UHPC. To curb the CO2 emission, UHPC is produced by substituting 50 wt% of Portland cement with a fine limestone powder. Fresh and hardened properties, shrinkage and frost durability have been evaluated. Mechanical properties were determined on a full-scale hybrid element using ultrasonic pulse velocity (UPV) and bond test (pull-off test). The results showed a significant increase of mechanical properties. Despite the applied thin layer of UHPC and volumetric restrain from the substrate normal concrete (NC) only limited surface shrinkage cracks were observed. The bond test and UPV showed good excellent values.

Place, publisher, year, edition, pages
EDP Sciences, 2022
Series
MATEC Web of Conferences, E-ISSN 2261-236X ; 364
Keywords
Ultra-high-performance concrete (UHPC), Normal concrete (NC), Shrinkage, Frost durability, Ultrasonic pulse velocity (UPV), Bond test (pull-off)
National Category
Other Materials Engineering
Research subject
Building Materials
Identifiers
urn:nbn:se:ltu:diva-93396 (URN)10.1051/matecconf/202236404014 (DOI)
Conference
International Conference on Concrete Repair, Rehabilitation and Retrofitting (ICCRRR 2022), Cape Town, South Africa, October 3-5, 2022
Funder
Swedish Transport AdministrationVinnova
Available from: 2022-10-03 Created: 2022-10-03 Last updated: 2024-04-16Bibliographically approved

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Citation style
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  • en-GB
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