This study deals with the criticality of binder-coarse aggregate interaction in the early age properties of 3D printable concrete (3DPC). The concrete with coarse aggregate (CA) behaves as two-phase material and has different rheological behavior. The transient early age concrete material properties are significant in simulating the plastic material yielding and elastic buckling failure patterns of 3DPC. Triaxial compression test (TCT) was adopted to measure apparent transient properties of 3DPC by Mohr-Coulomb criteria. Though this test methodology was adopted by some researches earlier for 3D printable mortars, a contradictory failure pattern was observed for 3DPC with CA of size 4 mm to 8 mm. The unconfined uniaxial compressive test (UUCT) was also performed to measure the green compressive strength and failure patterns were observed.

中文翻译：

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粗骨料含量对3D打印混凝土早龄期性能的影响研究

本研究探讨了粘合剂与粗骨料相互作用在 3D 打印混凝土 (3DPC) 早期性能中的重要性。粗骨料（CA）混凝土表现为两相材料，具有不同的流变行为。瞬态早期混凝土材料特性对于模拟 3DPC 的塑性材料屈服和弹性屈曲破坏模式具有重要意义。采用三轴压缩试验（TCT）按照莫尔-库仑准则测量3DPC的表观瞬态特性。虽然这种测试方法早期被一些研究用于 3D 打印砂浆，但对于 CA 尺寸为 4 毫米至 8 毫米的 3DPC 观察到矛盾的失效模式。还进行了无侧限单轴压缩试验（UUCT）来测量生坯压缩强度并观察破坏模式。