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The effect and mechanism of C–S–H-PCE nanocomposites on the early strength of mortar under different water-to-cement ratio
Journal of Building Engineering ( IF 6.4 ) Pub Date : 2021-09-24 , DOI: 10.1016/j.jobe.2021.103360
Jia-le Zhang 1 , Zi-ming Wang 1 , Yu-han Yao 1 , Rui-feng Tang 1 , Song-tao Li 1 , Xiao Liu 1 , Da-wei Sun 1
Affiliation  

C–S–H-PCE nanocomposites (CPNs) serving as nucleation sites are a promising material to accelerate the cement hydration and gain high early strength for cementitious materials. This study aimed to investigate the effects of CPNs on the properties and hydration of cement mortar under different water-to-cement (w/c) ratios. CPNs were prepared via the co-precipitation method in MAPEG-PCE solution and characterized by means of XRD, FT-IR, DLS, TEM, TGA, and TOC. The mechanism and effect of CPNs on the early hydration of cement mortar with w/c ratios of 0.50, 0.40, and 0.35 were assessed in terms of mechanical properties, isothermal calorimetry, setting time XRD, TGA, SEM, and MIP. The results showed that CPNs significantly promoted the early strength development of mortar and a higher enhancement ratio was brought at a lower w/c ratio. Calorimetry and setting results also showed a greater hydration acceleration of samples dosed CPNs with lower w/c ratio. From the analysis of XRD and TGA, the content of CH and C–S–H in the samples dosed CPNs increased with the decrease of w/c ratio in 6 h, while exhibited an opposite trend in 12 h and 3 d. MIP and SEM results showed that CPNs led to a refinement of pore structure and dense morphology, especially at a low w/c ratio. Moreover, the underlying acceleration mechanism of cement hydration versus w/c ratio was that the seeding ability was enhanced for the low distance between cement and CPNs at a low w/c ratio. According to this research, the use of CPNs may be more practical in high-strength concrete.



中文翻译:

不同水灰比下C-S-H-PCE纳米复合材料对砂浆早期强度的影响及机理

C-S-H-PCE 纳米复合材料 (CPNs) 作为成核位点是一种很有前途的材料,可以加速水泥水化并获得高早期强度的胶凝材料。本研究旨在研究 CPNs 在不同水灰比 (w/c) 下对水泥砂浆性能和水化的影响。CPNs 在 MAPEG-PCE 溶液中通过共沉淀法制备,并通过 XRD、FT-IR、DLS、TEM、TGA 和 TOC 进行表征。从力学性能、等温量热法、凝固时间 XRD、TGA、SEM 和 MIP 方面评估了 CPNs 对水灰比为 0.50、0.40 和 0.35 的水泥砂浆早期水化的机理和影响。结果表明,CPNs显着促进了砂浆的早期强度发展,并在较低的w/c比下带来了较高的增强率。量热法和固化结果还显示,加入具有较低水灰比的 CPN 样品的水合加速更大。从 XRD 和 TGA 的分析来看,加入 CPNs 的样品中 CH 和 C-S-H 的含量在 6 h 内随着 w/c 比的降低而增加,而在 12 h 和 3 d 内呈现出相反的趋势。MIP 和 SEM 结果表明 CPNs 导致孔结构和致密形态的细化,特别是在低 w/c 比的情况下。此外,水泥水化与水灰比的潜在加速机制是,在低水灰比下,水泥与 CPN 之间的距离较小,从而增强了播种能力。根据这项研究,在高强度混凝土中使用 CPNs 可能更实用。加入CPNs的样品中CH和C-S-H的含量在6 h内随着w/c比的降低而增加,而在12 h和3 d时呈相反趋势。MIP 和 SEM 结果表明 CPNs 导致孔结构和致密形态的细化,特别是在低 w/c 比的情况下。此外,水泥水化与水灰比的潜在加速机制是,在低水灰比下,水泥与 CPN 之间的距离较小,从而增强了播种能力。根据这项研究,在高强度混凝土中使用 CPNs 可能更实用。加入CPNs的样品中CH和C-S-H的含量在6 h内随着w/c比的降低而增加,而在12 h和3 d时呈相反趋势。MIP 和 SEM 结果表明 CPNs 导致孔结构和致密形态的细化,特别是在低 w/c 比的情况下。此外,水泥水化与水灰比的潜在加速机制是,在低水灰比下,水泥与 CPN 之间的距离较小,从而增强了播种能力。根据这项研究,在高强度混凝土中使用 CPNs 可能更实用。水泥水化与水灰比的潜在加速机制是,在低水灰比下,水泥与 CPN 之间的距离较小,从而增强了播种能力。根据这项研究,在高强度混凝土中使用 CPNs 可能更实用。水泥水化与水灰比的潜在加速机制是,在低水灰比下,水泥与 CPN 之间的距离较小,从而增强了播种能力。根据这项研究,在高强度混凝土中使用 CPNs 可能更实用。

更新日期:2021-09-24
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