Recovery of Biomass Fly Ash and HDPE in Innovative Synthetic Lightweight Aggregates for Sustainable Geotechnical Applications

Abstract

Sustainable development principles aim to re-utilize wastes to reduce their impact on the environment. In this context, the present contribution shows preliminary results on the preparation of innovative synthetic lightweight aggregates, starting from biomass-derived fly ash and high-density polyethylene (HDPE), to be used in geotechnical applications. The present work focuses on the manufacturing process of aggregate blends (including the selection of the right proportions of the two components) as well as on the relative determination of (i) physical–chemical properties (i.e., chemical composition, morphological analysis, mineral leachability, water absorption, specific gravity, grain size distribution); (ii) permeability features and (iii) mechanical properties (one-dimensional compression and shear strength behavior). The results, gathered from the new synthetic lightweight aggregates and compared with the corresponding ones obtained in a previous study conducted on natural and synthetic lightweight aggregates, appear promising for a potential utilization in geotechnical engineering.

Evaluation of the Superiority of Lightweight-Aggregate-Concrete Prestressed Box Girders in Terms of Durability and Prestress Loss

“…At present, the development of synthetic LWAs mainly uses industrial waste or municipal solid waste as raw materials. For example, slag, fly ash, reservoir sediment, waste TFT-LCD glass powder, paper sludge, tile-grinding sludge, water purification sludge, textile sludge, and other renewable resources are used to produce LWAs [5][6][7][8][9][10][11][12][13][14][15]. Many studies have shown the great potential of artificial aggregates made from industrial by-products or solid waste as substitutes for natural coarse aggregates [109].…”

“…In the past two decades, in order to reduce the consumption of natural resources, the source of materials for the production of synthetic LWAs has developed toward resource recycling [4]. For example, industrial waste and municipal solid waste are used as renewable resources to produce LWAs [5][6][7][8][9][10][11][12][13][14][15]. Generally speaking, the shell layer of synthetic high-strength LWAs and high-performance LWAs is hard and dense, but the interior is porous; thus, it is light in weight and has appropriate strength.…”

Sustainable Use of Sludge from Industrial Park Wastewater Treatment Plants in Manufacturing Lightweight Aggregates

“…However, with the growing concerns about sustainability, a wide range of urban and industrial waste types have been tested for their ability to partially or completely replace conventional raw materials for LWA production. These unconventional raw materials include ground granulated blast furnace slag [ 9 ], fly ash [ 10 ], incinerated ash [ 11 , 12 , 13 , 14 ], waste glass [ 15 ], sewage sludge [ 16 , 17 , 18 , 19 ], screen glass and polishing sludge [ 20 ], reservoir sediments [ 21 , 22 ], waste TFT-LCD glass powder and reservoir sediments [ 23 ], tile grinding sludge with reservoir sediments [ 24 ], waste drill cuttings [ 25 ], coal fly ash and waste glass [ 26 ], stone cutting sludge, plastic wastes, and sepiolite rejections [ 27 ], and clays and alternative raw materials [ 28 ]. Generally speaking, synthetic aggregates with a bulk density of 0.88–1.12 g/cm 3 can be used as structural concrete; aggregates with a bulk density of less than 0.88 g/cm 3 are mostly used to make thermal insulation elements.…”

Cleaner Design and Production of Lightweight Aggregates (LWAs) to Use in Agronomic Application

“…To deal with such problems, more attention has been paid to the development of sustainable clay bricks, such as those made from kindling from vine shoot [2], paper sludge [3], olive mill wastewater and spent coffee [4], grape and cherry seeds [5], sawdust and sugar cane ash [5], and textile laundry sludge [6]. Lightweight aggregates (LWAs) have also been extensively investigated through the addition of different organic and inorganic urban, industrial, and agro-waste, such as waste glass [7][8][9][10], bagasse, sludge and diatomaceous earth from the brewery industry [11], granite waste [12], fly ash [13,14], incinerator bottom ash [15,16], coal fly ash [17,18], waste engine [19][20][21], and sewage sludge [22][23][24][25][26]. The use of alternative energy sources for the production of lightweight aggregates has also begun to be studied.…”