预制小箱梁高温蒸养温度场及强度发展试验

High-temperature Steam Curing Temperature Field and Strength Development Test of Prefabricated Small Box Beams

摘要:

为揭示预制小箱梁高温蒸汽养护过程中非均匀温度场与强度发展的内在联系，开展了预制小箱梁足尺模型高温蒸养试验与有限元仿真分析。通过测点预埋温度传感器，并结合回弹法与标准立方体试块抗压强度试验，系统分析了试验梁不同部位的温度场演化与强度发展规律。结果表明，仿真与实测温度时程曲线吻合良好，验证了有限元模型的准确性；强度发展速率与温度梯度呈正相关，顶板强度增长最快，腹板次之，底板最慢，蒸养后48 h时，三者分别达到设计强度的98%、96%和90%，底板应作为早龄期质量管控的重点对象。采用内腔输入60℃蒸汽、蒸养时长约16 h的工艺，箱梁各部位强度在48 h内均达到设计强度的90%以上，可安全进行移梁、存储及预应力张拉等工序。

Abstract:

To reveal the intrinsic relationship between the non-uniform temperature field and strength development of prefabricated small box beams during high-temperature steam curing, a full-scale model high-temperature steam curing test and finite element simulation analysis on a prefabricated small box beams are conducted. By embedding temperature sensors at measurement points and combining the rebound method with standard cubic specimen compressive strength tests, the temperature field evolution and strength development patterns in different parts of the test beams are systematically analyzed. The results show that the simulated temperature-time curves are in good agreement with the measured ones, validating the accuracy of the finite element model. Strength development rate is highly correlated with the temperature gradient. The strength of the top plate grows the fastest, followed by the web, while that of the bottom plate grows the slowest. At 48 hours after steam curing, the design strengths of the three have respectively reached 98%, 96% and 90% of the designed strength. The bottom plate should be regarded as the key object for quality control in the early age period. By adopting the process of inputting 60 ℃ steam into the inner cavity and steam curing for approximately 16 hours, the strength of all parts of the box beam reaches more than 90% of the design strength within 48 hours, allowing the safe implementation of subsequent procedures such as beam moving, storage, and prestressing tensioning.