纳米工程化超高性能水泥基复合材料综述

A Review on Nano-Engineered Ultra-High Performance Cementitious Composites

超高性能水泥基复合材料 (Ultra-high performance cementitious composites, 简称UHPCC) 是近30年来最具创新和潜力的新一代水泥基复合材料。然而, 低孔隙和高密实度赋予UHPCC极高强度的同时, 也带来了材料毛细孔负压大、自收缩现象严重、水化速率快、温度应力大等问题。具有小尺寸效应和纳米效应的纳米填料有助于改善多尺度的水泥基原材料在纳米尺度上的连续性, 弥补水泥基复合材料的纳米结构缺陷, 从而自下而上地改性其力学、耐久等性能, 同时赋予水泥基复合材料功能特性。其中, 碳纳米管 (Carbon nanotubes, 简称CNTs) 既拥有碳纤维材料的固有特性, 又具有高导电导热、耐热耐蚀等特性, 是一种性能优异的纳米填料以及复合材料改性填料。基于此, 本文总结了UHPCC以及纳米填料, 尤其是CNTs复合水泥基材料的相关性能与研究现状, 分析了UHPCC超高性能的优化方法。纳米改性UHPCC有望从根本上设计水泥基复合材料的结构与性能, 在性能上取长补短、产生协同效应, 是研发UHPCC的创新性途径之一。

Ultra-high performance cementitious composites (UHPCC) are the most innovative and promising new generation of cementitious composites over the past three decades. However, while low porosity and high density contribute to the extremely high strength of UHPCC, they also lead to issues such as high capillary suction, severe autogenous shrinkage, rapid hydration rate, and large temperature stresses within the material. Nanofillers with small size and nano effects are helpful to improve the continuity of cementitious raw materials at the nanoscale across multiple scales. They make up for the nanostructure defects of cementitious composites, thereby modifying their mechanical and durability properties from the bottom up, and at the same time endowing cement-based composite materials with functional properties. Carbon nanotubes ( CNTs) not only have the inherent characteristics of carbon fiber materials, but also have high electrical conductivity, thermal conductivity, heat resistance, and corrosion resistance, which is an excellent type of nanofillers and an ideal reinforcing filler for composites. Based on this, this paper summarizes the relevant properties and research status of UHPCC, nanofillers reinforced cementitious composites, particularly CNTs reinforced cementitious composites, and analyzes the optimization methods for achieving the ultrahigh performance of UHPCC. Nano-modification of UHPCC holds promise for fundamentally designing the structure and properties of cementitious composites, achieving complementary strengths and synergistic effects in performance. It is one of the innovative approaches in the development of UHPCC.