A Review of the Thermal and Mechanical Characteristics of Alkali-Activated Composites at Elevated Temperatures
Alkali-activated materials (AAMs) are promoted as a sustainable alternative to ordinary Portland cement (OPC). They not only have excellent resistance to high temperatures and chemical corrosion, but they can also help to reduce greenhouse gas emissions and reduce energy consumption. Despite their s...
Saved in:
| Main Authors: | , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2025-02-01
|
| Series: | Buildings |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2075-5309/15/5/738 |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| _version_ | 1850226185877848064 |
|---|---|
| author | Ting Wu Si Tang Yao-Rong Dong Jiang-Hua Luo |
| author_facet | Ting Wu Si Tang Yao-Rong Dong Jiang-Hua Luo |
| author_sort | Ting Wu |
| collection | DOAJ |
| description | Alkali-activated materials (AAMs) are promoted as a sustainable alternative to ordinary Portland cement (OPC). They not only have excellent resistance to high temperatures and chemical corrosion, but they can also help to reduce greenhouse gas emissions and reduce energy consumption. Despite their superior resistance to high temperatures compared to conventional cement-based concretes, studies have indicated that AAMs still face challenges related to performance degradation under elevated temperatures. This paper systematically reviews and summarizes the thermal properties (i.e., thermal expansion, thermal stability, and thermal conductivity), mechanical performance, and deterioration mechanisms of various alkali-activated composite systems. The findings reveal significant variability in resistance to high temperatures among different AAM systems, originating from the diversity of precursor materials used. Generally, the strength deterioration of various AAMs below 400 °C is minimal or even slightly increased, while between 600 °C and 800 °C, the strength degradation is significantly accelerated. Upon reaching 800 °C, the rate of the strength deterioration of AAMs tends to stabilize, with some alkali-activated composites even exhibiting signs of strength recovery. After exposure to high temperatures of 800 °C, the retentions of the compressive strength and flexural strength of alkali-activated composites are in the ranges of about 20–60% and 20–40%, respectively. The degradation mechanisms at elevated temperatures primarily include crystalline-phase transformation, microstructural changes, and thermal incompatibility arising from the differing coefficients of thermal expansion between the matrix and the aggregates. Finally, this paper discusses effective strategies to enhance the resistance of AAMs to high temperatures and highlights both the opportunities and challenges for future research in this field. |
| format | Article |
| id | doaj-art-bec8d651c45d43cdb44ef4e34c7c416f |
| institution | OA Journals |
| issn | 2075-5309 |
| language | English |
| publishDate | 2025-02-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Buildings |
| spelling | doaj-art-bec8d651c45d43cdb44ef4e34c7c416f2025-08-20T02:05:09ZengMDPI AGBuildings2075-53092025-02-0115573810.3390/buildings15050738A Review of the Thermal and Mechanical Characteristics of Alkali-Activated Composites at Elevated TemperaturesTing Wu0Si Tang1Yao-Rong Dong2Jiang-Hua Luo3College of Civil and Construction Engineering, Hunan Institute of Technology, Hengyang 421002, ChinaCollege of Civil and Construction Engineering, Hunan Institute of Technology, Hengyang 421002, ChinaSchool of Civil Engineering, Xi’an University of Architecture and Technology, Xi’an 710055, ChinaCollege of Civil and Construction Engineering, Hunan Institute of Technology, Hengyang 421002, ChinaAlkali-activated materials (AAMs) are promoted as a sustainable alternative to ordinary Portland cement (OPC). They not only have excellent resistance to high temperatures and chemical corrosion, but they can also help to reduce greenhouse gas emissions and reduce energy consumption. Despite their superior resistance to high temperatures compared to conventional cement-based concretes, studies have indicated that AAMs still face challenges related to performance degradation under elevated temperatures. This paper systematically reviews and summarizes the thermal properties (i.e., thermal expansion, thermal stability, and thermal conductivity), mechanical performance, and deterioration mechanisms of various alkali-activated composite systems. The findings reveal significant variability in resistance to high temperatures among different AAM systems, originating from the diversity of precursor materials used. Generally, the strength deterioration of various AAMs below 400 °C is minimal or even slightly increased, while between 600 °C and 800 °C, the strength degradation is significantly accelerated. Upon reaching 800 °C, the rate of the strength deterioration of AAMs tends to stabilize, with some alkali-activated composites even exhibiting signs of strength recovery. After exposure to high temperatures of 800 °C, the retentions of the compressive strength and flexural strength of alkali-activated composites are in the ranges of about 20–60% and 20–40%, respectively. The degradation mechanisms at elevated temperatures primarily include crystalline-phase transformation, microstructural changes, and thermal incompatibility arising from the differing coefficients of thermal expansion between the matrix and the aggregates. Finally, this paper discusses effective strategies to enhance the resistance of AAMs to high temperatures and highlights both the opportunities and challenges for future research in this field.https://www.mdpi.com/2075-5309/15/5/738alkali-activated materialsthermal propertiesmechanical performancedeterioration mechanismshigh temperature |
| spellingShingle | Ting Wu Si Tang Yao-Rong Dong Jiang-Hua Luo A Review of the Thermal and Mechanical Characteristics of Alkali-Activated Composites at Elevated Temperatures Buildings alkali-activated materials thermal properties mechanical performance deterioration mechanisms high temperature |
| title | A Review of the Thermal and Mechanical Characteristics of Alkali-Activated Composites at Elevated Temperatures |
| title_full | A Review of the Thermal and Mechanical Characteristics of Alkali-Activated Composites at Elevated Temperatures |
| title_fullStr | A Review of the Thermal and Mechanical Characteristics of Alkali-Activated Composites at Elevated Temperatures |
| title_full_unstemmed | A Review of the Thermal and Mechanical Characteristics of Alkali-Activated Composites at Elevated Temperatures |
| title_short | A Review of the Thermal and Mechanical Characteristics of Alkali-Activated Composites at Elevated Temperatures |
| title_sort | review of the thermal and mechanical characteristics of alkali activated composites at elevated temperatures |
| topic | alkali-activated materials thermal properties mechanical performance deterioration mechanisms high temperature |
| url | https://www.mdpi.com/2075-5309/15/5/738 |
| work_keys_str_mv | AT tingwu areviewofthethermalandmechanicalcharacteristicsofalkaliactivatedcompositesatelevatedtemperatures AT sitang areviewofthethermalandmechanicalcharacteristicsofalkaliactivatedcompositesatelevatedtemperatures AT yaorongdong areviewofthethermalandmechanicalcharacteristicsofalkaliactivatedcompositesatelevatedtemperatures AT jianghualuo areviewofthethermalandmechanicalcharacteristicsofalkaliactivatedcompositesatelevatedtemperatures AT tingwu reviewofthethermalandmechanicalcharacteristicsofalkaliactivatedcompositesatelevatedtemperatures AT sitang reviewofthethermalandmechanicalcharacteristicsofalkaliactivatedcompositesatelevatedtemperatures AT yaorongdong reviewofthethermalandmechanicalcharacteristicsofalkaliactivatedcompositesatelevatedtemperatures AT jianghualuo reviewofthethermalandmechanicalcharacteristicsofalkaliactivatedcompositesatelevatedtemperatures |