The process of cement slurry curing into a solid has a direct effect on the initial state of stress in a composite concrete and steel structure. Failure models for critical infrastructure and wellbores could benefit from measurements of this initial stress because it greatly influences structural performance. Here, we present measurements of the initial stress state (total stress, effective stress, and pore pressure) of multiple cement formulations cured under a high-pressure of 40 MPa within a semi-rigid steel pipe. Our results show that cements cured in this restrained environment exhibit dense microstructures with low permeability (nano-Darcy), develop an anisotropic stress state greater than zero and less than the curing pressure, and undergo a staged curing process where hydration and mechanical behaviors evolve from a slurry into a pre-stressed porous medium. Both drained and undrained scenarios were investigated, revealing a feedback from the semi-rigid boundary towards improved cement performance.

水泥浆固化成固体的过程直接影响混凝土和钢结构复合材料的初始应力状态。关键基础设施和井筒的故障模型可以从这种初始应力的测量中受益，因为它极大地影响了结构性能。在这里，我们展示了在 40 MPa 高压下在半刚性钢管内固化的多种水泥配方的初始应力状态（总应力、有效应力和孔隙压力）的测量值。我们的结果表明，在这种受限环境中固化的水泥表现出具有低渗透性（纳米达西）的致密微观结构，产生大于零且小于固化压力的各向异性应力状态，并经历阶段固化过程，其中水化和机械行为从浆液演变为预应力多孔介质。对排水和不排水情况进行了研究，揭示了半刚性边界对提高水泥性能的反馈。