Analysis of thermal conductivity of porous concrete using laboratory measurements and microstructure models

Abstract Porous concrete pavement has been used to alleviate urban heat island (UHI) effect in the near-surface temperature field. Due to high porosity and heterogeneity, thermal properties of porous concrete may vary depending on the microstructure of aggregates and air voids. This paper developed an innovative method to calculate the effective thermal conductivity of porous concrete considering two-dimensional (2-D) heterogeneous microstructure. An image-aided approach was used to randomly generate the three-phase (aggregates, cement paste, and air) microstructure model of porous concrete. Finite-element (FE) models were developed to calculate thermal conductivity of porous concrete by simulating the steady heat transfer process. Laboratory experiments were conducted to measure thermal conductivity of porous concrete and its components. The prediction results were compared to experimental measurements and close agreements without statistical differences were observed. The effects of microstructure feature on thermal conductivity of porous concrete were studied. Although the thermal conductivity of porous concrete decreases as the porosity increases in general, the variation of thermal conductivity is affected by the tortuosity and orientation of air void and aggregate contacts. The study findings clearly indicate that the heterogeneous microstructure of porous concrete need be considered for accurate prediction of thermal transport behavior.

[1]  S. Kakaç,et al.  Heat Conduction, Third Edition , 1992 .

[2]  Yongli Zhao,et al.  Effect of air voids on the high-temperature creep behavior of asphalt mixture based on three-dimensional discrete element modeling , 2016 .

[3]  Liv Haselbach,et al.  Cyclic Heat Island Impacts on Traditional versus Pervious Concrete Pavement Systems , 2011 .

[4]  Andrew Dawson,et al.  Thermal properties of asphalt pavements under dry and wet conditions , 2016 .

[5]  John T Harvey,et al.  Cooling Effect of Permeable Asphalt Pavement under Dry and Wet Conditions , 2013 .

[6]  Hao Wang,et al.  Pavement temperature prediction: Theoretical models and critical affecting factors , 2019, Applied Thermal Engineering.

[7]  Fang Wang,et al.  Theoretical and experimental study on multi-phase model of thermal conductivity for fiber reinforced concrete , 2017 .

[8]  Takashi Asaeda,et al.  Characteristics of permeable pavement during hot summer weather and impact on the thermal environment , 2000 .

[9]  CôtéJean,et al.  Thermal conductivity of bitumen concrete , 2013 .

[10]  Dale P. Bentz,et al.  Transient plane source measurements of the thermal properties of hydrating cement pastes , 2007 .

[11]  Guo-sheng Jiang,et al.  The Albedo of Pervious Cement Concrete Linearly Decreases with Porosity , 2015 .

[12]  Dae-Wook Park,et al.  Evaluation of Asphalt Mixture Modified with Graphite and Carbon Fibers for Winter Adaptation: Thermal Conductivity Improvement , 2017 .

[13]  L. Castro,et al.  Two-Dimensional Virtual Microstructure Generation of Particle-Reinforced Composites , 2016, J. Comput. Civ. Eng..

[14]  Jiaqi Chen,et al.  Analytical approach for evaluating temperature field of thermal modified asphalt pavement and urban heat island effect , 2017 .

[15]  Jing Yang,et al.  Experimental study on properties of pervious concrete pavement materials , 2003 .

[16]  Jia Yu,et al.  Characterizing thermal behaviors of various pavement materials and their thermal impacts on ambient environment , 2018 .

[17]  Shaopeng Wu,et al.  Effect of freezing-thawing and ageing on thermal characteristics and mechanical properties of conductive asphalt concrete , 2017 .

[18]  Donath Mrawira,et al.  Thermal Properties and Transient Temperature Response of Full-Depth Asphalt Pavements , 2002 .

[19]  Venkatesh Kodur,et al.  Effect of Temperature on Thermal Properties of Different Types of High-Strength Concrete , 2011 .

[20]  Liang Li,et al.  Determination of Effective Thermal Conductivity of Asphalt Concrete with Random Aggregate Microstructure , 2015 .

[21]  Vernon R. Schaefer,et al.  Temperature Behavior of Pervious Concrete Systems , 2009 .

[22]  John T Harvey,et al.  Corrigendum: The use of reflective and permeable pavements as a potential practice for heat island mitigation and stormwater management , 2013 .

[23]  Omkar Deo,et al.  Compressive behavior of pervious concretes and a quantification of the influence of random pore structure features , 2010 .

[24]  Jiaqi Chen,et al.  Evaluation of thermal conductivity of asphalt concrete with heterogeneous microstructure , 2015 .

[25]  Jun Chen,et al.  Directional distribution of three-dimensional connected voids in porous asphalt mixture and flow simulation of permeability anisotropy , 2018, International Journal of Pavement Engineering.

[26]  Zhuangzhuang Liu,et al.  Temperature Characteristics of Porous Portland Cement Concrete during the Hot Summer Session , 2017 .

[27]  Joseph Luca,et al.  Effect of aggregate type, gradation, and compaction level on thermal properties of hot-mix asphalts , 2006 .

[28]  Liang Li,et al.  Virtual testing of asphalt mixture with two-dimensional and three-dimensional random aggregate structures , 2017 .

[29]  Jacob E. Hiller,et al.  Water availability near the surface dominates the evaporation of pervious concrete , 2016 .

[30]  Kevin Macdonald,et al.  Structural Analysis of Pervious Concrete Pavement , 2011 .

[31]  S. Nassiri,et al.  Thermal Conductivity of Pervious Concrete for Various Porosities , 2017 .

[32]  Kay Wille,et al.  Influence of pore tortuosity on hydraulic conductivity of pervious concrete: Characterization and modeling , 2016 .

[33]  Jiong Hu,et al.  The effect of the cementitious paste thickness on the performance of pervious concrete , 2015 .

[34]  Zuotai Zhang,et al.  Development of the random simulation model for estimating the effective thermal conductivity of insulation materials , 2014 .