The advancement of concrete technology such as 3D concrete printing has rekindled research interest in the early-age mechanical properties of concrete. However, the non-adaptability of early-age (plastic) concrete to classical mechanical measurements causes the quest for alternative approaches. This study is a new and unique approach, using rheological methods, aimed at investigating the early development of shear and viscoelastic properties of concrete from the time of mixing up to the initial setting time. Dynamic shear rheometry (coupled with rotational tests), taking advantage of the normal stress measurement, was used to evaluate the shear and viscoelastic properties. Viscosity modifying agent (VMA), superplasticiser (SP) and increased water content were incorporated to achieve a robust test program. The Mohr-Coulomb shear parameters, shear yield parameters, shear modulus, creep and stress relaxation properties were evaluated from rheometry tests. Theoretical and experimental analyses of a vane-in-cup rheometry reveal that the resultant normal stress, during an elastic response, originates from the self-weight of the sample and is dependent on the sample's weight distribution. The results, therefore, show that it is not sufficient to estimate the self-weight of the concrete for normal stress evaluation and that the shear and creep properties of concrete mainly develop within half-time of the initial set while stress relaxation is inherent and remains fairly unchanged. Challenges and prospects of this approach were also discussed.

3D 混凝土打印等混凝土技术的进步重新点燃了对混凝土早期力学性能的研究兴趣。然而，早期（塑料）混凝土对经典力学测量的不适应性导致寻求替代方法。这项研究是一种新的独特方法，使用流变学方法，旨在研究混凝土从搅拌时间到初始凝固时间的剪切和粘弹性特性的早期发展。动态剪切流变测量（结合旋转测试），利用法向应力测量，用于评估剪切和粘弹性。粘度调节剂 (VMA)、超塑化剂 (SP) 和增加的水含量被纳入以实现稳健的测试程序。Mohr-Coulomb 剪切参数，通过流变测试评估剪切屈服参数、剪切模量、蠕变和应力松弛特性。叶片杯流变测量的理论和实验分析表明，在弹性响应过程中产生的法向应力源自样品的自重，并取决于样品的重量分布。因此，结果表明，估计混凝土的自重以进行法向应力评估是不够的，混凝土的剪切和蠕变性能主要在初始凝固的半时间内发展，而应力松弛是固有的并保持不变相当不变。还讨论了这种方法的挑战和前景。叶片杯流变测量的理论和实验分析表明，在弹性响应过程中产生的法向应力源自样品的自重，并取决于样品的重量分布。因此，结果表明，估计混凝土的自重以进行法向应力评估是不够的，混凝土的剪切和蠕变性能主要在初始凝固的半时间内发展，而应力松弛是固有的并保持不变相当不变。还讨论了这种方法的挑战和前景。叶片杯流变测量的理论和实验分析表明，在弹性响应过程中产生的法向应力源自样品的自重，并取决于样品的重量分布。因此，结果表明，估计混凝土的自重以进行法向应力评估是不够的，混凝土的剪切和蠕变性能主要在初始凝固的半时间内发展，而应力松弛是固有的并保持不变相当不变。还讨论了这种方法的挑战和前景。表明估计混凝土的自重以进行法向应力评估是不够的，混凝土的剪切和蠕变性能主要在初始凝固的一半时间内发展，而应力松弛是固有的，并且基本保持不变。还讨论了这种方法的挑战和前景。表明估计混凝土的自重以进行法向应力评估是不够的，混凝土的剪切和蠕变性能主要在初始凝固的一半时间内发展，而应力松弛是固有的，并且基本保持不变。还讨论了这种方法的挑战和前景。