Structural Concretes with Waste-Based Lightweight Aggregates: From Landfill to Engineered Materials

Abstract

This research provides possible opportunities in the reuse of waste and particularly muds, coming from both ornamental stone (granite sludges from sawing and polishing operations) and ceramic production (porcelain stoneware tile polishing sludge), for the manufacture of lightweight aggregates. Lab simulation of the manufacturing cycle was performed by pelletizing and firing the waste mixes in a rotative furnace up to 1300 degrees C, and determining composition and physicomechanical properties of lightweight aggregates. The best formulation was used to produce and test lightweight structural concretes according to standard procedures. Both granite and porcelain stoneware polishing sludges exhibit a suitable firing behavior due to the occurrence of SiC (an abrasive component) which, by decomposing at high temperature with gas release, acts as a bloating promoter, resulting in aggregates with particle density < 1 Mg/m3. However, slight variations of mixture composition produce aggregates with rather different properties, going from values close to those of typical commercial expanded clays (particle density 0.68 Mg/m3; strength of particle 1.2 MPa) to products with high mechanical features (particle density 1.25 Mg/m3; strength of particle 6.9 MPa). The best formulation (50 wt.% porcelain stoneware polishing sludge +50 wt.% granite sawing sludge) was used to successfully manufacture lightweight structural concretes with suitable properties (compressive strength 28 days > 20 MPa, bulk density 1.4-2.0 Mg/m3).

A Suppression Method for Elution of F−, [B(OH)4]−, AsO43−, and CrO42− from Industrial Wastes Using Some Inhibitors and Crushed Stone Powder

“…However, because of the continuous depletion of natural resources, the limited landfill land available, and increased transportation costs, there is a demand for the effective utilization of CSP. In recent years, there have been an increasing number of studies that focus on the recycling of CSP in concrete instead of in silica powder or sand [35][36][37][38][39]. However, further utilization of CSP in inhibiting the elution of hazardous ions is rarely found.…”

An investigation on the performance of lightweight mortar-based geopolymer containing high-volume LECA aggregate against high temperatures

“…Since that date, LWACs have been widely used in many countries such as the USA, the UK, and Sweden. At the present time, the LWAs can be synthesized using different natural precursors as clay and shale (de'Gennaro et al 2009). Compared to the traditional concrete made with normal weight aggregate, the LWAC has a fairly high porosity (Chung et al 2021) and low density as a result of embedding porous lightweight ingredients (Mehta and Monteiro 2014).…”

Mechanical and Physical Properties of Light-Weight Ceramic Aggregates Prepared from Waste Materials

“…The main aim of the presented research is to propose a new way for recycling windshield glass waste where significant improvement of mechanical and physical properties are obtainable based on the usage of additional waste material in the new product manufacturing. One possible solution [4][5][6][7][8] includes manufacturing alumina silicate-based lightweight aggregates (LWA) that can be used in both building and gardening industries. Another constituent balancing the chemical composition of the ceramic batch includes other waste material from the coal/ore industry, especially coal mine slates or any other alumina silicate-based waste material [8][9][10][11][12][13].…”