Nanocomposites as Substituent of Cement: Structure and Mechanical Properties

Abstract

To date, the scientific research in the field of recycling of construction and demolition wastes was focused on the production of concrete, cements, and bricks. The attainment of these products was limited to the addition of suitable binder contents, such as lime or cement, compaction, and possibly heat treatment, without a concrete recycling method. In this paper, new cement materials consisting of 2.5 weight% composite and originating from construction and demolition waste powder, were prepared and investigated in view of applications in the construction industry as a substituent of cement. The materials with recycled powder from construction and demolition wastes were characterized by X-ray diffraction (XRD), infrared (IR) and nuclear magnetic resonance (NMR) spectroscopy. The XRD data indicate vitroceramic structures with varied crystalline phases. The NMR relaxometry data show four reservoirs of water associated with bounded water and with three types of pores in the composite construction material. The micro-Vickers hardness was measured to reflect the influence of composite nature in the local mechanical properties of the composite-cement for the mixture with Portland cement and (EC) expired cement.

Physico-chemical characterization and possible uses of sludge processed from an urban sewage treatment plant

“…These IR bands were assigned to symmetric stretching vibrations of [ ] silicate units containing tetrahedral units with zero to four non-bridging oxygens, namely, tectosilicate, disilicate, metasilicate, pyrosilicate, and orthosilicate units denoted as Q4, Q3, Q2, Q1, and Q0 respectively [26] . The IR features allow distinguishing bands located at about cm −1 , cm −1 , cm −1 , near 900 cm −1 , near 850 cm −1 of each dominant at the tectosilicate, disilicate, metasilicate, pyrosilicate, and orthosilicate units [27] .…”

Development of Iron–Silicate Composites by Waste Glass and Iron or Steel Powders

“…The prominent IR bands situated between 3000-3750 cm −1 and the weak IR band located at around 2900 cm −1 correspond to the H-O-H bending vibrations and hydroxyl units. The broader IR band centered at about ~3435 cm −1 is assigned to the Si-OH stretching [27] and the H-O stretching vibrations from adsorbed water molecules on the surface [28][29][30]. These vibrational frequencies were gradually diminished for the Fo composite.…”

“…28, 6296 9 of 17 absorption edge range. The detailed knowledge regarding the optical band gap, the direct and indirect transitions and the tangent line of the plots which make the estimations of Eg values in the disordered systems were shown in the references[36][37][38][39][40][41][42].…”

Nanocomposites Derived from Construction and Demolition Waste for Cement: X-ray Diffraction, Spectroscopic and Mechanical Investigations

“…The development of other classes of cement-based materials as a viable alternative to a circular economy must be researched in the field, according to the European Union. The use of renewable raw materials such as coal gangue, construction and demolition waste, fly ash, metallurgical waste, and glasses is a solution for a circular economy [3][4][5].…”