The physicomechanical characteristics and
microstructures of the materials are examined based on natural water immersion
and freezethaw cycle by laboratory tests, and the
deterioration rates are compared to investigate the deterioration
characteristics of organic thermal insulation materials (polyphenolics,
polyurethane, and polystyrene). The findings indicate that: (1) The water
absorption curves of the thermal insulation materials display three stages of
fast, gradual, and stable. The polyphenolics have the longest water absorption
duration at 192 h. After 50 freezethaw cycles, the
bulk water absorption rate of polystyrene is the highest, reaching 67.50%. (2)
The binary linear model predicts the relationship between thermal conductivity,
freezethaw cycles, and mass water/ice rate for the
organic insulation materials. The rigid polystyrene and the thawed polyurethane
materials are most vulnerable to freezethaw cycles.
(3) The polystyrene has the lowest thermal conductivity of 0.029 1 W/(m·K) without a freezethaw cycle. However,
after 50 freezethaw cycles, the thawed polystyrene and
rigid polyphenolics exhibit the lowest thermal conductivities, with values of
0.034 4 W/(m·K) and 0.047 3 W/(m·K), respectively. (4) The material with the highest compressive
strength, measuring 0.476 MPa is polyurethane. The performance degradation of
thermal insulation of materials is mainly affected by the bubble type, pore
size, and pore fracture at the microlevel.
LIU Zonghan
,
HAN Fenglei
,
LI Jiazheng
,
HUANG Yong
,
ZHANG Xuefu
,
GENG Yongqi
. Deterioration Law of Organic Thermal Insulation
Materials for Cold Region Tunnels under Natural Water
Immersion and FreezeThaw Conditions[J]. Tunnel Construction, 2022
, 42(8)
: 1453
-1460
.
DOI: 10.3973/j.issn.2096-4498.2022.08.015
