固碳插层材料抑制混凝土碳化反应的基础研究

One of the most important features of modern high-performance concrete is high volume fraction of mineral addition，which often causes faster carbonation rate of concrete and hence threatens the durability of concrete structures.It is vital to enhance carbonation resistancy of modern concrete so as to a longer service life and being environmentally-friendly.This study aims to catch carbonate ions in concrete and to fix them in intercalation layers, in order to improve carbonation resistancy by means of the properties of anion-exchange and structure re-construction of the intercalated layered materials.It is to study the interactions between the inorganic intercalated layered material and hydrating cement system, and to reveal the mechanism of the exchange and immobilization of carbonate ions, and to master the main factors affecting exchange and immobilization of carbonate ions, and to establish the law of effects of the intercalation material on microstructure and performance of concrete.On this basis, it is to develop a design methodology of concrete modification with intercalated layered materials, and to build the computation model of the carbonation process, and to explore a new type of functional adjusting admixture for preventing carbonation. The results are expected not only to solve the problem of rapid carbonation of concrete with high volume fraction of mineral admixture, but also to build an inherent defence system against chemical aggression into concrete structures.

大掺量矿物掺合料是现代高性能混凝土的主要特征之一，但由此带来的碳化速率加快的问题威胁着混凝土结构的耐久性。所以，增强抗碳化能力对于现代混凝土长寿命化和低环境负荷化至关重要。本项目旨在利用无机插层材料的阴离子交换和结构重建特性，捕捉混凝土中的碳酸根并嵌锁于插层材料层板间，使之"固化"由此增强混凝土的抗碳化性能。为此，拟开展无机插层材料与水化水泥体系的相互作用的研究，探明碳酸根离子发生离子交换和固化的机制，掌握影响离子交换和结构重建过程的主要因素，揭示无机插层材料对混凝土微结构和性能的影响规律。在此基础上，发展插层材料改性混凝土的设计方法，建立其碳化过程计算机仿真模型，探索以无机插层材料为核心的可调控抗碳化能力的混凝土性能调节剂的开发途径，并开展插层材料固化其他类型阴离子的探索性研究。研究成果不仅有助于解决大掺量矿物掺合料混凝土碳化速率加快的问题，而且有望构建本征的混凝土化学侵蚀防御体系。

本项目深入系统地研究了插层功能材料Mg-Al型LDHs(Layered double hydroxides)对侵蚀性离子的吸附作用及其对混凝土耐久性的影响。主要研究了LDHs对水泥水化过程的影响规律；探索了LDHs材料抑制混凝土碳化反应的微观机理。提出了LDHs固碳过程的热力学定量化模型；设计了LDHs 基复合材料改性混凝土与化学侵蚀防御体系。揭示了LDHs 化合物固化硫酸根和氯离子的潜在能力与机理。提出一种改性Ca-Al型LDHs 化合物的微观表征和固化氯离子特性。提出了矿渣水化生成LDHs的新理念及其对混凝土耐久性的提升。这些新的理论对于深入研究新型插层材料对水泥混凝土耐久性的提高，具有较为重要的学术价值。发表学术论文17篇，其中被SCI、EI 和ISTP 收录10篇，申请专利1项；培养博士研究生2名，硕士研究生2名。研究成果在实验和实践过程中，显示出良好的结果。