Macro-Properties and Microstructures of Foam Concrete Containing Porosity Sludge Gasification Particles
Abstract
1. Introduction
2. Experimental Work
2.1. Materials
2.1.1. Properties of Cement
2.1.2. Character of SGP
2.1.3. Properties of Superplasticizer and Foaming Agent
2.2. Preparation of Foam Concrete
2.3. Test Methods
2.3.1. Test for Dry Density
2.3.2. Tests for Mechanical Properties
2.3.3. Test for Drying Shrinkage
2.3.4. Test for Thermal Conductivity
2.3.5. Pore Structure Detection and Analysis
3. Results and Analyses
3.1. Dry Density of Foam Concrete
3.2. Mechanical Properties of Foam Concrete
3.3. Drying Shrinkage of Foam Concrete
3.4. Thermal Conductivity of Foam Concrete
3.5. Micro-Pore Structure of Foam Concrete
4. Conclusions
- (1)
- The foam concrete achieved the target density grade of A07. With an increase in SGP content from 0% to 30%, the compressive and flexural strengths of foam concrete decreased, while lower drying shrinkage and thermal conductivity were observed. The compressive strength had a decrease of 35.2–52.6%, and the flexural strength had a decrease of 28.6–42.8%. The drying shrinkage reached a reduction of 7.5–32.2%, and the thermal conductivity presented a decrease of 17.3–23.4%.
- (2)
- With an increase in SGP content from 0% to 30%, the average pore diameter of foam concrete had an increase of 44.5%, while the pores less than 200 μm decreased in percentage from 60.69% to 39.28%, and those over 200 μm increased by 21.41%. The pore roundness increased from 1.49 to 1.72, indicating a transition from isolated spherical pores to interconnected irregular pores.
- (3)
- The mechanisms of SGPs functions in foam concrete can be explained with two aspects: an enhanced volume stability through a combination of skeletal restraint and internal curing effect, and a reconstruction of pore structures with connected pores of larger diameter. Therefore, a trade-off should be decided between strength reduction and shrinkage/thermal improvements.
- (4)
- Aimed at developing a low-carbon and environmentally friendly building material, the foam concrete can be produced with an optimal content of 10% SGPs. This provides a foam concrete with a strength grade of FC3 and a decrease of 33.3% in thermal conductivity compared to standard requirements, and an equivalent drying shrinkage with a decrease of 7.5% at a curing age of 90 days.
- (5)
- The effects of SGPs on strength, shrinkage and thermal insulation of foam concrete were studied for the first time. The mechanisms involved between strength reduction and shrinkage/thermal improvements are necessary to be fully explored in the future. A potential practical application can be expected on producing foam concrete with an optimal content of SGPs.
Author Contributions
Funding
Data Availability Statement
Conflicts of Interest
References
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Chemical Composition | SiO2 | Al2O3 | CaO | Fe2O3 | MgO | SO3 | K2O |
---|---|---|---|---|---|---|---|
Content/% | 20.61 | 4.03 | 62.07 | 3.25 | 4.15 | 2.13 | 0.84 |
Specific Surface Area (m2/kg) | Apparent Density (kg/m3) | Setting Time (min) | Flexural Strength (MPa) | Compressive Strength (MPa) | |||
---|---|---|---|---|---|---|---|
Initial | Final | 3 d | 28 d | 3 d | 28 d | ||
353 | 3046 | 219 | 275 | 4.6 | 8.5 | 27.1 | 46.2 |
Aggregate | Fineness Modulus | Apparent Density (kg/m3) | Bulk Density (kg/m3) | Saturated Surface-Dry Water Absorption (%) |
---|---|---|---|---|
SGP | 2.0 | 2094 | 1073 | 5.47 |
Chemical Composition | SiO2 | Al2O3 | Fe2O3 | MgO | CaO | Na2O | K2O | MnO | TiO2 | P2O5 |
---|---|---|---|---|---|---|---|---|---|---|
Content (%) | 47.27 | 15.23 | 4.66 | 3.65 | 7.31 | 1.48 | 2.14 | 0.1 | 0.56 | 11.67 |
Solubility (%) | Bulk Density (g/L) | pH | Dilution Ratio | Settlement After 1 h (mm) | Bleeding Rate After 1 h (%) |
---|---|---|---|---|---|
100 | 32–44 | 7.5 | 1:80 | 21 | 32 |
Symbol | SGP Mass Fractions (%) | Cement (kg/m3) | SGP (kg/m3) | Water (kg/m3) | Foam (kg/m3) | Superplasticizer (kg/m3) |
---|---|---|---|---|---|---|
CFC | 0 | 583.3 | 0 | 204.1 | 58.34 | 2.92 |
SGFC_10 | 10 | 513.9 | 69.3 | 179.8 | 59.63 | 2.57 |
SGFC_20 | 20 | 459.3 | 124.1 | 160.7 | 60.66 | 2.30 |
SGFC_30 | 30 | 415.1 | 168.1 | 145.3 | 61.48 | 2.07 |
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Yang, M.; Li, Z.; Wang, Y.; Wang, K.; Ma, J.; Li, F. Macro-Properties and Microstructures of Foam Concrete Containing Porosity Sludge Gasification Particles. Buildings 2025, 15, 2914. https://doi.org/10.3390/buildings15162914
Yang M, Li Z, Wang Y, Wang K, Ma J, Li F. Macro-Properties and Microstructures of Foam Concrete Containing Porosity Sludge Gasification Particles. Buildings. 2025; 15(16):2914. https://doi.org/10.3390/buildings15162914
Chicago/Turabian StyleYang, Manman, Zhiyong Li, Yunlei Wang, Kele Wang, Juntao Ma, and Fenglan Li. 2025. "Macro-Properties and Microstructures of Foam Concrete Containing Porosity Sludge Gasification Particles" Buildings 15, no. 16: 2914. https://doi.org/10.3390/buildings15162914
APA StyleYang, M., Li, Z., Wang, Y., Wang, K., Ma, J., & Li, F. (2025). Macro-Properties and Microstructures of Foam Concrete Containing Porosity Sludge Gasification Particles. Buildings, 15(16), 2914. https://doi.org/10.3390/buildings15162914