Recycled aggregate concrete has great significance from the environmental protection perspective. However, the current research findings on its hygrothermal properties are sparse. In this study, the apparent density, thermal conductivity, mass moisture content, water vapor permeability coefficient, water absorption coefficient, and liquid water diffusion coefficient of recycled aggregate concrete were determined by experimental methods. The effect of temperature and humidity on thermal conductivity was also studied. Furthermore, the fitting relations of the thermal conductivity of recycled aggregate concrete with the two variables of temperature and relative humidity were presented. The isothermal moisture absorption curve and the fitting relationship of water vapor permeability coefficient with relative humidity were also developed. The results indicate that the thermal conductivity of the eight recycled concrete specimens in the dry state at 25°C ranges from 0.994 to 1.242 W/(m·K). The thermal conductivity increases with the increase in temperature. When the temperature rises from 25°C to 35°C, the thermal conductivity of recycled aggregate concrete increases by 3.8%–13.5%. With the increase of relative humidity, the thermal conductivity of recycled aggregate concrete shows an increasing trend, followed by a steady state, and finally the increasing trend, showing a cubic function relationship between them. When the relative humidity increases from 0% to 95%, the thermal conductivity increases by about 20%. The mass moisture content and the water vapor permeability coefficient increase with relative humidity. The results of this study can provide basic information for the study on the heat and moisture transfer of recycled aggregate concrete, and enhance the database of hygrothermal properties of building materials.
BerardiUNaldiM (2017) The impact of the temperature dependent thermal conductivity of insulating materials on the effective building envelope performance. Energy and Buildings144: 262–275.
2.
CaurieM (1970) A new model equation for predicting safe storage moisture levels for optimum stability of dehydrated foods. International Journal of Food Science & Technology5(3): 301–307.
3.
China Academy of Building Research (2011) GB/T 15229-2011, Lightweight Aggregate Concrete Small Hollow Block. Beijing, China: Standards Press of China.
4.
China Academy of Building Research (2016) GB50176-2016, Code for Thermal Design of Civil Building. Beijing, China: Standards Press of China.
5.
ChuSHPoonCSLamCS, et al. (2021) Effect of natural and recycled aggregate packing on properties of concrete blocks. Construction and Building Materials278: 122247.
6.
CuiY (2017) Research on the effect of coupled heat and moisture transfer on energy consumption and indoor thermal and moisture environment of public buildings. Master Thesis, Shenyang Jianzhu University, Shenyang, China.
7.
DamdelenO (2018) Investigation of 30% recycled coarse aggregate content in sustainable concrete mixes. Construction and Building Materials184: 408–418.
8.
FengC (2014) Study on the test methods for the hygric properties of porous building materials. PhD Thesis, South China University of Technology, Guangzhou.
9.
GhorbelEWardehGGomartH, et al. (2020) Formulation parameters effects on the performances of concrete equivalent mortars incorporating different ratios of recycled sand. Journal of Building Physics43(6): 545–572.
10.
GuoZKongXZhangJ, et al. (2020) Life-cycle assessment of concrete building blocks incorporating recycled concrete aggregates—A case study in China. In: Pacheco-TorgalF.DingY.ColangeloF.TuladharRKoutamanisA (eds), Advances in Construction and Demolition Waste Recycling, pp. 515–535. Elsevier.
11.
HasnaouiAGhorbelEWardehG (2021) Performance of metakaolin/slag-based geopolymer concrete made with recycled fine and coarse aggregates. Journal of Building Engineering42: 102813.
12.
HoHJIizukaAShibataE, et al. (2021) Utilization of CO2 in direct aqueous carbonation of concrete fines generated from aggregate recycling: Influences of the solid–liquid ratio and CO2 concentration. Journal of Cleaner Production312(20): 127832.
13.
ISO, ISO 15148: 2002(E) (2002) Hygrothermal Performance of Building Materials and Products-Determination of Water Absorption Coefficient by Partial Immersion. Geneva: International Organization for Standardization.
14.
ISO, ISO 12571: 2013(E) (2013) Hygrothermal Performance of Building Materials and Products-Determination of Hygroscopic Sorption Properties. Geneva: International Organization for Standardization.
15.
ISO, ISO 12572: 2016(E) (2016) Hygrothermal Performance of Building Materials and Products-Determination of Water Vapour Transmission Properties. Geneva: International Organization for Standardization.
16.
KouSCPoonCS (2010) Properties of concrete prepared with PVA-impregnated recycled concrete aggregates. Cement and Concrete Composites32(8): 649–654.
17.
LiK (2009) Research of hygrothemal parameters of building envelop and heat and moisture transfer in East China. PhD Thesis, Tongji University, Shanghai, China.
18.
LiuYMaCWangD, et al. (2016) Nonlinear effect of moisture content on effective thermal conductivity of building materials with different pore size distributions. International Journal of Thermophysics37: 56.
19.
MaKHuangXShenJ, et al. (2021) The morphological characteristics of brick-concrete recycled coarse aggregate based on the digital image processing technique. Journal of Building Engineering44: 103292.
20.
MengDWuXQuanH, et al. (2021) A strength-based mix design method for recycled aggregate concrete and consequent durability performance. Construction and Building Materials281: 122616.
21.
MiličevićIBjegovićDSiddiqueR (2015) Experimental research of concrete floor blocks with crushed bricks and tiles aggregate. Construction and Building Materials94: 775–783.
22.
Ministry of Housing and Urban-Rural Development of the People’s Republic of China (2011) JGJ/T 14-2011, Technical Specification for Concrete Small-Sized Hollow Block Masonry Building. Beijing, China: China Architecture & Building Press.
23.
Nanjing Fiberglass Research & Design Institute Co. Ltd (2006a) GB/T 20313–2006, Hygrothermal Performance of Building Materials and Products Determination of Moisture Content by Drying at Elevated Temperature. Beijing, China: Standards Press of China.
24.
Nanjing Fiberglass Research & Design Institute Co. Ltd (2006b) GB/T 20312–2006, Hygrothermal Performance of Building Materials and Products Determination of Hygroscopic Sorption Properties. Beijing, China: Standards Press of China.
25.
NguyenLHBeaucourA-LOrtolaS, et al. (2017) Experimental study on the thermal properties of lightweight aggregate concretes at different moisture contents and ambient temperatures. Construction and Building Materials151: 720–731.
26.
OlofinnadeOOgaraJ (2021) Workability, strength, and microstructure of high strength sustainable concrete incorporating recycled clay brick aggregate and calcined clay. Cleaner Engineering and Technology3: 100123.
27.
PoonCSKouSCWanHW, et al. (2009) Properties of concrete blocks prepared with low grade recycled aggregates. Waste Management29(8): 2369–2377.
28.
Shanghai Research Institute of Building Sciences Co., Ltd (2015) GB/T 17146–2015, Test Methods for Water Vapour Transmission Properties of Building Materials and Products. Beijing, China: Standards Press of China.
29.
SosaMEVillagrán ZaccardiYAZegaCJ (2021) A critical review of the resulting effective water-to-cement ratio of fine recycled aggregate concrete. Construction and Building Materials313(27): 125536.
30.
SunLGuoHLiuY (2017) Study on seismic behavior of steel frame with external hanging concrete walls containing recycled aggregates. Construction and Building Materials157(30): 790–808.
31.
TangYXiaoJZhangH, et al. (2022) Mechanical properties and uniaxial compressive stress-strain behavior of fully recycled aggregate concrete. Construction and Building Materials323: 126546.
32.
TangZLiWTamVWY, et al. (2020) Advanced progress in recycling municipal and construction solid wastes for manufacturing sustainable construction materials. Resources Conservation and Recycling6: 100036.
33.
WangY (2013) Research on the effect of the palisade structure moisture transfer on the indoor thermal environment and air-conditioning load. PhD Thesis, Xi’an University of Architecture and Technology, Xian, China.
34.
WangYHuangJWangD, et al. (2019) Experimental investigation on thermal conductivity of aerogel-incorporated concrete under various hygrothermal environment. Energy188: 115999.
35.
WangYHuangJWangD, et al. (2020) Experimental study on hygrothermal characteristics of coral sand aggregate concrete and aerated concrete under different humidity and temperature conditions. Construction and Building Materials230: 117034.
36.
XiaoJLiJLanY (2013) Research on recycled aggregate concrete – A review. Concrete168(10): 17–20.
37.
XiaoJSongZZhangF (2010) An experimental study on thermal conductivity of concrete. Journal of Building Materials13(1): 17–21.
38.
XiaoZLingTCPoonCS, et al. (2013) Properties of partition wall blocks prepared with high percentages of recycled clay brick after exposure to elevated temperatures. Construction and Building Materials49: 56–61.
39.
YouFZhengJ (2018) Experimental study of thermal conductivity of recycled concrete. Journal of Fuzhou University (Natural Science Edition)46(3): 391–395.
40.
YuC (2010) Heat and Mass Transfer in Porous Materials and Its Numerical Analysis. Beijing: Tsinghua University Press.
41.
YuS (2018) Study on Thermal and Wet Physical Parameters of Wall Materials. Shenyang, China: Northeastern University Press.
42.
ZhangW (2019) Study on wet physical properties of adobe building materials. Master Thesis, Beijing University of Civil Engineering and Architecture, Beijing.
43.
ZhaoZCourardLGroslambertS, et al. (2020) Use of recycled concrete aggregates from precast block for the production of new building blocks: An industrial scale study. Resources Conservation and Recycling157: 104786.
44.
ZhengYZhuoJZhangP (2021) A review on durability of nano-SiO2 and basalt fiber modified recycled aggregate concrete. Construction and Building Materials304: 124659.
45.
ZhuLDaiJBaiG, et al. (2015a) Experimental study on thermal conductivity of recycled concrete. Journal of Building Materials18(5): 852–856+904.
46.
ZhuLDaiJBaiG, et al. (2015b) Study on thermal properties of recycled aggregate concrete and recycled concrete blocks. Construction and Building Materials94: 620–628.
