Organic cross-linking decreases the thermal conductivity of calcium silicate hydrates
Organic cross-linking decreases the thermal conductivity of calcium silicate hydrates
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DOI：
10.1016/j.cemconres.2023.107324
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发表时间：
2023-12
影响因子：
11.4
通讯作者：
Amir Moshiri;A. Morshedifard;Damian Stefaniuk;Santiago El Awad;T. Phatak;Kamil J. Krzywiński;Debora Frigi Rodrigues;M. J. A. Qomi;K. J. Krakowiak
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作者：
Amir Moshiri;A. Morshedifard;Damian Stefaniuk;Santiago El Awad;T. Phatak;Kamil J. Krzywiński;Debora Frigi Rodrigues;M. J. A. Qomi;K. J. Krakowiak
我们通过实验、微机械均质化理论和分子模拟研究了硅酸钙水合物 (C-S-H) 和有机交联 C-S-H 的传导热传输。我们发现，当与短链有机硅烷交联时，C-S-H 的固有导热率低于其无定形极限。观察到的减少与双有机硅烷分子的烷基链长度相关。为了了解导致这种还原的基本分子过程，我们构建了交联 C-S-H 的真实分子结构，并根据光谱和比重瓶测量对其进行验证。原子模拟表明，propagons（传播热载体）和扩散子（扩散热载体）对热传输的贡献减少，以及 locons（局部振动模式）的放大，是限制 C-S-H 热传导的主要驱动因素。所提出的研究结果为用于水泥复合材料的纳米工程新型外加剂和用于热效率建筑围护结构的弹性轻质水泥细观结构提供了新的潜在方向。
We study the conductive heat transport through calcium silicate hydrate (C-S-H) and organically cross-linked C-S-H via experiments, micromechanical homogenization theory, and molecular simulations. We find that C-S-H's intrinsic thermal conductivity falls below its amorphous limit when cross-linked with short-chain organosilanes. The observed reduction correlates with the alkyl chain length of the bis-organosilane molecule. To understand the underlying fundamental molecular processes accountable for such a reduction, we construct realistic molecular structures of cross-linked C-S-H and validate them against the spectroscopic and pycnometery measurements. The atomistic simulations indicate that the reduction in the contribution of propagons (propagating heat carriers) and diffusons (diffusive heat carriers) to heat transport, and the amplification of locons (localized vibrational modes), are the main driving factors allowing to limit the heat conduction in C-S-H. Presented findings offer new potential directions to nanoengineering novel admixtures for cement composites and resilient lightweight cementitious mesostructures for thermally efficient building envelopes.