骨料特性影响混凝土体积稳定性的研究进展

Research Progress on the Influence of Aggregate Characteristics on the Volume Stability of Concrete

提升混凝土体积稳定性是提高现代混凝土耐久性、实现高性能化的重要研究内容,也是亟待解决的关键问题。骨料特性是影响混凝土体积稳定性的重要因素之一。骨料形态、级配、矿物组成、孔隙结构、弹性模量和热学性能均会从不同角度影响混凝土的体积稳定性。过去的工作大多集中在骨料某个或某几个特性对混凝土体积稳定性的影响,未能充分阐明骨料特性对现代混凝土体积稳定性的影响机制。随着天然骨料的日趋短缺以及人造骨料技术的逐渐提升,利用工业废渣制备人造骨料是实现混凝土可持续发展的另一途径。对人造功能骨料进行组成、结构与功能设计与制备,不仅可通过骨料特性改善混凝土的性能,还可减少建设工程对天然骨料的依赖,拓宽骨料来源,并为工业废渣资源化处理提供新思路,是促进现代混凝土工业可持续发展的关键举措。本文综述了骨料不同特性(如骨料形态、级配、矿物组成、孔隙结构、弹性模量和热学性能等)对混凝土体积稳定性的影响,阐明了骨料特性与混凝土体积稳定性的映射关系,阐述了骨料特性的单一作用及共同作用对现代混凝土体积稳定性的影响机制。并从骨料角度入手,提出了通过降低混凝土的热膨胀系数、调整混凝土内部相对湿度和改善界面过渡区特性等方法提升混凝土体积稳定性的措施。同时也对功能型人造废渣骨料的设计与制备进行了归纳与展望。

Improving the volume stability of concrete is an important research content for improving the durability of modern concrete and realizing high performance,and it is also a key issue to be solved urgently.Aggregate characteristics are one of the most important factors affecting volume stability of concrete.The shape,gradation,mineral composition,pore structure,elastic modulus and thermal properties of aggregate will influence the volume stability of concrete from different angles.Previous work mostly focused on the influence of one or several characteristics of aggregate on the volume stability of concrete,but failed to explain the influence mechanism of aggregate characteristics on the volume stability of modern concrete.With the increasing shortage of natural aggregates and the gradual improvement of artificial aggregate technology,using industrial waste residue to prepare artificial aggregate is another way to realize the sustainable development of concrete.The design and preparation of composition,structure and function of artificial functional aggregates can not only improve the performance of concrete through the characteristics of aggregates,but also reduce the dependence of construction projects on natural aggregates,broaden the sources of aggregates and provide resources for industrial waste treatment.This new idea is a key measure to promote the sustainable development of the modern concrete industry.In this paper,the effects of different aggregate properties(such as aggregate shape,gradation,mineral composition,pore structure,elastic modulus and thermal properties)on the volume stability of concrete are summarized.The mapping relationship between aggregate properties and volume stability of concrete is clarified.The influence mechanism of single and combined effect of aggregate properties on the volume stability of modern concrete is expounded.From the point of view of aggregates,some methods are proposed to improve the volume stability of concrete,such as reducing the thermal expansion coefficient of concrete,adjusting the relative humidity inside concrete and improving the characteristics of the interface transition zone.At the same time,the design and preparation of functional artificial waste residue aggregates are summarized and prospected.