Characterization of 3D microstructure, thermal conductivity, and heat flow of cement-based foam using imaging technique

Abstract

This study presents the results of the 3D microstructure, thermal conductivity, and heat flow in cement-based foams and examines their changes with a range of densities. Images were captured using X-ray micro computed tomography (micro-CT) imaging technique on cement-based foam samples prepared with densities of 400, 600, and 800 kg/m³. These images were later simulated and quantified using 3D data visualization and analysis software. Based on the analysis, the pore volume of 11000 µm³ was determined across the three densities, leading to optimal results. However, distinct pore diameters of 15 µm for 800 kg/m³, and 20 µm for 600 and 400 kg/m³ were found to be optimum. Most of the pores were spherical, with only 10% appearing elongated or fractured. In addition, a difference of 15% was observed between the 2D and 3D porosity results. Moreover, a difference of 5% was noticed between the experimentally measured thermal conductivity and the numerically predicted value and this variation was constant across the three cast densities. The 3D model showed that heat flows through the cement paste solids and with an increase in porosity this flow reduces.

Graphical abstract

Keywords

3D pore volume distribution / X-ray tomography / 3D shape factor / heat flow

References

[1] Amran Y, Farzadnia N, Abang Ali A. Properties and applications of foamed concrete: A review. Construction & Building Materials, 2015, 101: 990–1005

[2] Awang H, Mydin M A O, Roslan A F. Effect of additives on mechanical and thermal properties of lightweight foamed concrete. Pelagia Research Library Advances in Applied Science Research, 2012, 3: 3326–3338

[3] She W, Chen Y, Zhang Y, Jones M. Characterization and simulation of microstructure and thermal properties of foamed concrete. Construction & Building Materials, 2013, 47: 1278–1291

[4] Samson G, Phelipot-Mardelé A, Lanos C. Thermal and mechanical properties of gypsum–cement foam concrete: effects of surfactant. European Journal of Environmental and Civil Engineering, 2016, 21(12): 1–20

[5] Batool F, Bindiganavile V. Quantification of factors influencing the thermal conductivity of cement-based foam. Cement and Concrete Composites, 2018, 91: 76–86

[6] Falliano D, de Domenico D, Ricciardi G, Gugliandolo E. Improving the flexural capacity of extrudable foamed concrete with glass-fiber bi-directional grid reinforcement: An experimental study. Composite Structures, 2019, 209: 45–59

[7] Nambiar E, Ramamurthy K. Air-void characterisation of foam concrete. Cement and Concrete Research, 2007, 37(2): 221–230

[8] Wee T, Tamilselvan T, Lim H, Babu D. Air-void system of foamed concrete and its effect on mechanical properties. ACI Materials Journal, 2006, 103(1): 45–52

[9] Hilal A, Thom N, Dawson A. On void structure and strength of foamed concrete made without/with additives. Construction & Building Materials, 2015, 85: 157–164

[10] Bentz D, Quenard D, Kunzel H, Baruchel J, Peyrin F, Martys N, Garboczi E J. Microstructure and transport properties of porous building materials. II: Three-dimensional X-ray tomographic studies. Materials and Structures, 2000, 33(3): 147–153

[11] Nguyen T, Ghazlan A, Kashani A, Bordas S, Ngo T. 3D meso-scale modelling of foamed concrete based on X-ray computed tomography. Construction & Building Materials, 2018, 188: 583–598

[12] Batool F, Bindiganavile V. Air-void size distribution of cement-based foam and its effect on thermal conductivity. Construction & Building Materials, 2017, 149: 17–28

[13] Chung S, Lehmann C, Abd Elrahman M, Stephan D. Pore characteristics and their effects on the material properties of foamed concrete evaluated using micro-CT images and numerical approaches. Applied Sciences (Basel, Switzerland), 2017, 7(6): 550

[14] She W, Zhang Y, Jones M. Three-dimensional numerical modeling and simulation of the thermal properties of foamed concrete. Construction & Building Materials, 2014, 50: 421–431

[15] CAN/CSA A3000. Cementitious Materials Compendium, Canadian Standards. Ontario: Association Mississauga, 2013

[16] ASTM C869. Standard Specification for Foaming Agents Used in Making Preformed Foam for Cellular Concrete. West Conshohocken, PA: ASTM International, 2012

[17] Batool F, Bindiganavile V. Thermal conductivity of hydrated paste in cement-based foam microstructure. Advances in Civil Engineering Materials, 2018, 7(1): 17–32

[18] Kong L, Ostadhassan M, Li C, Tamimi N. Pore characterization of 3D-printed gypsum rocks: A comprehensive approach. Journal of Materials Science, 2018, 53(7): 5063–5078

[19] Carson J, Lovatt S, Tanner D, Cleland A. Thermal conductivity bounds for isotropic, porous materials. International Journal of Heat and Mass Transfer, 2005, 48(11): 2150–2158

Acknowledgements

The authors thank the NED University of Engineering and Technology for providing the simulation facilities. We also thank the Natural Sciences and Engineering Research Council NSERC-Canada for providing funding.

RIGHTS & PERMISSIONS

2021 Higher Education Press