To reduce the negative effect of a large temperature
gradient on the strength and deformation of tunnel cement mortar material, a
phase change material (PCM) with automatic temperatureregulating
ability is introduced to prepare PCM/cement mortar mixture. The PCMs are
firstly made from paraffin wax, highdensity
polyethylene, and expanded graphite by melt blending method. Then, they are
mixed into the cement paste material to produce the PCM/cement composite
slurry. A thermal response test platform is built to test the performance of
the thermal strain development with temperature. The heat storage performance
is evaluated by the results of thermal response. Furthermore, the thermal and
mechanical behaviors of the composite slurry with different mixing proportions
of PCM are compared with those of common cement slurry with 0% PCM. It can be
concluded that PCM/cement composite slurry can store heat during the process in
the form of latent heat, which is 34.82 J/g in this test. The thermal strain of
composite slurry with different mixing proportions of PCM is 36.63% lower than
that of the common cement slurry, indicating that the PCMs can effectively
reduce the sample′s surface temperature and thermal
strain. The PCM/cement composite slurry can provide a new method for
controlling temperature deformation and the development of cracks in energy
tunnels and related crack repairing engineering.
ZHU Ying
,
ZHAO Jinxing
,
QU Jingying
,
QIAN Xiaohua
,
ZENG Changnü
,
REN Lei
. Thermodynamic Properties of Phase Change
Material/Cement Composite Slurry[J]. Tunnel Construction, 2022
, 42(9)
: 1570
-1577
.
DOI: 10.3973/j.issn.2096-4498.2022.09.008
