According to what is extensively and logically assumed, a better anti-thixotropic behaviour than thixotropy was expected for shear-thickening cement pastes. However, the shear-thickening Portland and volcanic cement pastes studied here showed apparent thixotropic behaviour when step-up tests were performed. This unexpected result was tentatively justified assuming that, just at the beginning of the step-stress, virtually instantaneous particle aggregation (for step-up tests) and disaggregation (for step-down tests) take place. In other words, the existence of fast jamming or unblocking mechanisms developed by shear-thickening cement pastes was hypothesised. Then, it was supposed that the initial reorganisation of cement particles was followed by a progressive erosion of the jammed state (step-up) or progressive aggregation of the unblocking state (step-down) due to the constant action of shear stress. These ideas were used to model an empirical equation for the dependence of viscosity on shear stress, which can be used for cement applications.

中文翻译：

---

剪切稀化/剪切增稠水泥浆体的时间依赖性粘度行为

根据广泛且逻辑上的假设，剪切增稠水泥浆体预期具有比触变性更好的抗触变性。然而，本文研究的剪切增稠波特兰和火山水泥浆体在进行升压测试时表现出明显的触变行为。这个意想不到的结果暂时是合理的，假设在阶跃应力开始时，几乎瞬时发生颗粒聚集（对于升压测试）和分解（对于降压测试）。换句话说，假设存在由剪切增稠水泥浆产生的快速堵塞或解锁机制。然后，据推测，由于剪切应力的恒定作用，水泥颗粒的初始重组之后是堵塞状态（逐步上升）的逐渐侵蚀或解锁状态（逐步下降）的逐渐聚集。这些想法被用来模拟粘度与剪切应力依赖性的经验方程，该方程可用于水泥应用。