Pizoń Jan, Gołaszewski Jacek, Alwaeli Mohamed, Szwan Patryk
Faculty of Civil Engineering, Silesian University of Technology, 44-100 Gliwice, Poland.
Faculty of Energy and Environmental Engineering, Silesian University of Technology, 44-100 Gliwice, Poland.
Materials (Basel). 2020 Mar 22;13(6):1448. doi: 10.3390/ma13061448.
Sand has been considered to be something of an immeasurable quantity. There are many indications that this view is no longer valid and that the limiting of natural aggregates usage is doubly justified. Firstly, the extraction of natural aggregates is expensive and has a huge impact on the environment. The main issues in sand and gravel mining are the large areas that are affected, ground water level changes, illegal mining, unsuitability of desert and marine sand, and costs of transport. Secondly, metallurgical waste can be used as a substitute for natural aggregates. This is doubly beneficial-the waste is recycled and the use of natural aggregates is reduced. Waste is stored in landfills that take up large areas and there is also the possibility of ground and groundwater pollution by hazardous compounds. The research presented in this article focuses on the technological conditions of using metallurgical waste in its original form and as a component of recycled concrete aggregate (RCA). The use of metallurgical sludge waste or crushed or round RCA to produce concrete deteriorates the consistency and does not significantly affect the air content and density of the concrete mix. RCA lowers the density of hardened concrete. Metallurgical sludge waste or RCA usage adversely affect the absorbability and permeability of concrete. Concrete containing metallurgical sludge waste is of higher compressive strength after 7 and 28 days, with up to 60% of waste as a sand replacement. RCA concrete achieved higher compressive strength also.
沙子一直被认为是一种数量难以估量的物质。有许多迹象表明，这种观点已不再成立，限制天然骨料的使用有双重合理性。首先，天然骨料的开采成本高昂，且对环境有巨大影响。砂石开采中的主要问题包括受影响的面积大、地下水位变化、非法开采、沙漠和海砂不适用以及运输成本。其次，冶金废料可作为天然骨料的替代品。这有双重好处——废料得到回收利用，天然骨料的使用量减少。废料被储存在占用大片土地的垃圾填埋场，而且还有可能被有害化合物污染土壤和地下水。本文所介绍的研究聚焦于以冶金废料的原始形式及其作为再生混凝土骨料（RCA）的一种成分时的使用技术条件。使用冶金污泥废料或破碎的或圆形的RCA来生产混凝土会降低混凝土的稠度，并且对混凝土拌合物的含气量和密度没有显著影响。RCA会降低硬化混凝土的密度。使用冶金污泥废料或RCA会对混凝土的吸水性和渗透性产生不利影响。含有冶金污泥废料的混凝土在7天和28天后具有更高的抗压强度，废料替代沙子的比例可达60%。RCA混凝土也能达到更高的抗压强度。
