面向隧道结构修复的3D打印混凝土强度检测试验研究

Study on Strength Detection of 3D Printing Concrete for Tunnel Structure Repair

3D打印技术为隧道结构修复开辟了新途径,其中3D打印混凝土的性能是关键因素,特别是其超早龄期力学性能。探究了采用超声波波速检测超早龄期3D打印水泥基材料力学性质的可能性,对普通水泥净浆、不掺加外加剂普通砂浆和用于3D打印的掺外加剂砂浆中的超声波波速特征以及无侧限单轴抗压强度进行试验,研究了终凝后相同时间的超声波波速特征和无侧限单轴抗压强度的发展规律及二者之间的联系。结果表明:在相同测试时间下,超声波波速在不同的超早龄期水泥基材料中表现出明显的差异性,并能够在超声波波速与水泥基材料超早龄期特定力学指标之间构建对应的数理关系,这为采用超声波法检测超早龄期水泥基材料力学特性提供了依据。

3D printing technology has introduced a new approach for the repair of tunnel structures,where the performance of 3D printed concrete,particularly its mechanical properties at ultra-early age,is crucial.The feasibility of using ultrasonic wave velocity to detect the mechanical properties of ultra-early age 3D printing cement-based materials is investigated.Tests are conducted on the ultrasonic wave velocity characteristics and unconfined uniaxial compressive strength of ordinary cement paste,ordinary mortar without additives,and additive-enhanced mortar used for 3D printing.The study examined the relationship between the ultrasonic wave velocity characteristics and the development of unconfined uniaxial compressive strength at the same time after final setting.Results indicated significant differences in ultrasonic wave velocity among different ultra-early age cement-based materials under the same testing conditions,establishing a corresponding mathematical relationship between ultrasonic wave velocity and specific mechanical properties of ultra-early age cement-based materials.This provides a basis for using ultrasonic methods to detect the mechanical properties of ultra-early age cement-based materials.