复合泡沫混凝土用作寒区高铁路基保温研究

Study on Thermal Insulation of Composite Foam Concrete for High-speed Railway Subgrade in Cold Region

针对影响寒区铁路路基稳定性及列车行车安全的土体冻胀融沉现象,提出内嵌聚苯乙烯的粉煤灰泡沫混凝土复合拼装式保温板作为基床表层保温强化层。对粉煤灰泡沫混凝土进行物理力学特性试验,并讨论内插聚苯乙烯复合板的铺设方式。结果表明,粉煤灰泡沫混凝土的导热系数在粉煤灰掺量达到50%时最大,为0.2472W/(m-K);抗压强度在粉煤灰掺量30%时最大,为14.10MPa;抗折强度在粉煤灰掺量为20%时最大,为4.8MPa。综合考虑各参数变化趋势,建议采用粉煤灰掺量为30%的泡沫混凝土作为寒区路基保温强化层材料基体,并将聚苯乙烯保温块填充以增加保温效果,按照工厂化生产、装配式施工铺设于基床表层,以确保路基稳定性及行车安全性。

Aiming at the phenomenon of frost heave and thaw settlement of soil which affects the stability of railway subgrade and the safety of train running in cold region, the composite thermal insulation board of fly ash foam concrete embedded with polystyrene is put forward as the thermal insulation strengthening layer of the surface layer of subgrade. The physical and mechanical properties of fly ash foamed concrete were tested, and the laying method of interpolated polystyrene composite board was discussed. The results show that the thermal conductivity of fly ash foamed concrete is the highest when the fly ash content reaches 50%, which is 0. 247 2 W/( m*K). The compressive strength is the highest when the fly ash content reaches 30%, which is 14. 10 MPa. The flexural strength is the highest when the fly ash content reaches 20%, which is 4. 8 MPa. Considering the variation trend of each parameter, it is suggested that the foamed concrete with 30% fly ash should be used as the base material of the thermal insulation strengthening layer, and the polystyrene heat preservation block should be filled to increase the heat preservation effect, and be laid on the surface of subgrade bed according to the industrial production and assembly construction to ensure the stability of subgrade and driving safety.