Abstract
The reuse of waste in civil construction brings environmental and economic benefits. However, for these to be used in concrete, it is necessary a previous evaluation of their physical and chemical characteristics. Thus, this study aimed to characterize and analyze the waste foundry exhaust sand (WFES) for use in self-compacting concrete (SCC). Foundry exhaust sand originates from the manufacturing process of sand molds and during demolding of metal parts. It is a fine sand rich in silica in the form of quartz collected by baghouse filter. Characterization of WFES was conducted through laser granulometry, scanning electron microscopy (SEM) in the energy dispersive spectroscopy (EDS) mode, X-ray diffraction (XRD), X-ray fluorescence (XRF), Fourier transform infrared spectroscopy (FTIR), thermogravimetry (TG) and derivative thermogravimetry (DTG) techniques. The waste was classified as non-hazardous and non-inert, with physical and chemical properties suitable for use in SCC composition, as fine aggregate or mineral addition. Five mixtures of SCC were developed, in order to determine the waste influence in both fresh and hardened concrete. The properties in the fresh state were reached. There was an increase in compressive strength and sulfate resistance, a decrease in water absorption of self-compacting concrete by incorporating WFES as 30% replacement.
Highlights
The results showed that, with 30% of sand replacement by Waste foundry exhaust sand (WFES), self-compacting concrete (SCC) presented smaller void ratio and greater sulfate attack resistance
Understanding the waste characteristics, it is possible to identify its influence on fresh and hardened concrete properties, such as compressive strength, water absorption, permeability and durability, shrinkage, and potential reactions when subjected to sudden changes in temperature
Waste foundry exhaust sand is a low-particle waste with a chemical composition similar to natural sand and it is classified as non-hazardous, non-inert and non-corrosive
Summary
The properties of a material and its microstructure are closely related. Microstructural characterization involves the determination of crystalline structure, chemical composition, particle size and morphology, as well as phase distribution [1]. The traits present in the microstructure have different characteristics and require a large number of complementary techniques for their characterization [2]. Investigations have analyzed alternative materials, which could partially replace the main constituents of concrete, since that they meet the requirements for acceptable structural, construction and safety performance. They must present characteristics required by the current standards [3]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
