Alani Ahmed Anees, Lesovik Ruslan, Lesovik Valery, Fediuk Roman, Klyuev Sergey, Amran Mugahed, Ali Mujahid, de Azevedo Afonso R G, Vatin Nikolai Ivanovich
University of Anbar, Ramadi 31001, Iraq.
Department of Building Materials Science, Products and Structures, Belgorod State Technological University Named after V.G. Shukhov, 308012 Belgorod, Russia.
Materials (Basel). 2022 Aug 31;15(17):6018. doi: 10.3390/ma15176018.
Due to renovation and fighting in the world, a huge accumulation of construction and demolition waste is formed. These materials are effectively used as aggregates, but there is very little information about the use of scrap concrete to create cementless binders. The purpose of the work is to be a comprehensive study of the composition and properties of concrete wastes of various fractions with the aim of their rational use as cementless binders. The scientific novelty lies in the fact that the nature of the processes of structure formation of a cementless binder based on sandy fractions of the screening of fragments of destroyed buildings and structures, as a complex polyfunctional system, has been theoretically substantiated and experimentally confirmed. Different percentages of non-hydrated clinker minerals in concrete scrap were determined. In the smallest fraction (less than 0.16 mm), more than 20% of alite and belite are present. Waste of the old cement paste is more susceptible to crushing compared to the large aggregate embedded in it, therefore, particles of the old cement paste and fine aggregate predominate in the finer fractions of the waste. Comprehensive microstructural studies have been carried out on the possibility of using concrete scrap as a completely cementless binder using scanning electron microscopy, X-ray diffraction analysis, and differential thermal analysis. It has been established that for cementless samples prepared from the smallest fractions (less than 0.315 mm), the compressive strength is 1.5-2 times higher than for samples from larger fractions. This is due to the increased content of clinker minerals in their composition. The compressive strength of the cementless binder after 28 days (7.8 MPa), as well as the early compressive strength at the age of 1 day after steaming (5.9 MPa), make it possible to effectively use these materials for enclosing building structures.
由于世界各地的翻新和战斗，形成了大量的建筑和拆除废物堆积。这些材料被有效地用作骨料，但关于使用废弃混凝土制造无水泥粘结剂的信息却非常少。这项工作的目的是对不同粒径的混凝土废料的成分和性能进行全面研究，以便将其合理用作无水泥粘结剂。该研究的科学新颖之处在于，作为一个复杂的多功能系统，基于被摧毁建筑物和结构碎片筛分后的砂质部分的无水泥粘结剂结构形成过程的本质，已在理论上得到证实并通过实验得到确认。测定了混凝土废料中不同百分比的未水化熟料矿物。在最小粒径部分（小于0.16毫米），存在超过20%的阿利特和贝利特。与其中嵌入的大骨料相比，旧水泥浆废料更容易破碎，因此，旧水泥浆颗粒和细骨料在废料的较细粒径部分占主导。已使用扫描电子显微镜、X射线衍射分析和差热分析，对将混凝土废料用作完全无水泥粘结剂的可能性进行了全面的微观结构研究。已确定，对于由最小粒径部分（小于0.315毫米）制备的无水泥样品，其抗压强度比由较大粒径部分制备的样品高1.5至2倍。这是由于其成分中熟料矿物含量增加。无水泥粘结剂28天后的抗压强度（7.8兆帕）以及蒸养1天后的早期抗压强度（5.9兆帕），使得这些材料能够有效地用于围护建筑结构。
