Qi Fengyan, Song Wenbing, Chen Zhiwei, Zhang Jian
Jiyang College, Zhejiang A&F University, Shaoxing 311800, China.
School of Civil Engineering and Architecture, Zhejiang University, Hangzhou 310058, China.
Materials (Basel). 2024 Aug 7;17(16):3927. doi: 10.3390/ma17163927.
The dissolution of calcium ions in concrete in a low-alkalinity environment is an important factor causing a significant increase in the porosity of internal concrete, leading to a deterioration in its mechanical properties and affecting the durability of the concrete structure. In order to improve the reliability of concrete durability design and significantly increase the service life of concrete structures located in soft water environments, it is crucial to establish an analytical method to predict the elastic modulus () of cement slurry systems suffering from calcium dissolution. Firstly, the hydrated cement particles are regarded as a three-phase composite sphere composed of unhydrated cement particles (UC), a high-density hydrated layer (H-HL), and a low-density hydrated layer (L-HL). By introducing the equivalent inclusion phase (EQ) composed of UC and H-HL, the three-phase composite sphere model can be simplified into an equivalent hydrated cement particle model composed of EQ and L-HL. Finally, the of the two-phase composite sphere composed of the equivalent hydrated cement particles and the porosity of the dissolved cement slurry system are solved by using elasticity theory. The effectiveness of the developed analytical method is verified by comparing it with third-party numerical results. Based on this method, the effects of hydration degree, volume ratio of calcium hydroxide (CH) to hydrated calcium silicate (C-S-H), and volume ratio of inner C-S-H to outer C-S-H on the of the dissolved cement slurry system are analyzed. The parameter analysis indicates that among the three influencing parameters, the hydration degree has the greatest effect on the of the dissolved cement slurry system. This study provides an analytical method for predicting , which can provide some references for the durability design of concrete after calcium dissolution.
钙离子在低碱环境下于混凝土中的溶解是导致混凝土内部孔隙率显著增加的重要因素，会致使其力学性能劣化并影响混凝土结构的耐久性。为提高混凝土耐久性设计的可靠性并显著延长位于软水环境中的混凝土结构的使用寿命，建立一种预测遭受钙溶解的水泥浆体系统弹性模量（ ）的分析方法至关重要。首先，将水化水泥颗粒视为由未水化水泥颗粒（UC）、高密度水化层（H - HL）和低密度水化层（L - HL）组成的三相复合球体。通过引入由UC和H - HL组成的等效夹杂相（EQ），三相复合球体模型可简化为由EQ和L - HL组成的等效水化水泥颗粒模型。最后，利用弹性理论求解由等效水化水泥颗粒组成的两相复合球体的 以及溶解水泥浆体系统的孔隙率。通过与第三方数值结果对比，验证了所开发分析方法的有效性。基于该方法，分析了水化程度、氢氧化钙（CH）与水化硅酸钙（C - S - H）的体积比以及内部C - S - H与外部C - S - H的体积比对溶解水泥浆体系统 的影响。参数分析表明，在这三个影响参数中，水化程度对溶解水泥浆体系统的 影响最大。本研究提供了一种预测 的分析方法，可为钙溶解后混凝土的耐久性设计提供一些参考。
