Influence of Carbonated Bottom Slag Granules in 3D Concrete Printing

Abstract

This study investigates the possibility of utilising bottom slag (BS) waste from landfills, and a carbonation process advantageous for the use of artificial aggregates (AAs) in printed three-dimensional (3D) concrete composites. In general, the main idea of granulated aggregates is to reduce the amount of CO2 emissions of printed 3D concrete objects (wall). AAs are made from construction materials, both granulated and carbonated. Granules are made from a combination of binder (ordinary Portland cement (OPC), hydrated lime, burnt shale ash (BSA)) and waste material (BS). BS is a waste material left over after the municipal waste burning process in cogeneration power plants. Whole printed 3D concrete composite manufacturing consists of: granulating artificial aggregate, aggregate hardening and sieving (adaptive granulometer), carbonation of AA, mixing 3D concrete, and 3D printing. The granulating and printing processes were analysed for hardening processes, strength results, workability parameters, and physical and mechanical properties. Printings with no granules (reference 3D printed concrete) were compared to 3D printed concretes with 25% and 50% of their natural aggregate replaced with carbonated AA. The results showed that, theoretically, the carbonation process could help to react approximately 126 kg/m3 CO2 from 1 m3 of granules.

A Review of Chloride Penetration of Recycled Concrete with Enhancement Treatment and Service Life Prediction

“…Carbonization treatment, as another promising method for mortar enhancement, has been extensively investigated during the past decades [ 67 ]. Calcium hydroxide (CH) with high CO 2 -reactivity is prone to precipitating calcium silicate in mortar [ 68 ], which increases the total volume of the mortar by 3%, thus densifying the mortar and improving the properties of RA [ 69 ]. Actually, CH is prone to natural reaction during the service of the parent concrete.…”

“…Although a large number of studies have been reported on the influence of carbonization conditions (such as temperature, humidity, etc.) on the carbonization rate [ 69 , 80 , 81 ], the relationship between the phase of the carbonization product, carbonization conditions, and carbonization rate has not been fully studied.…”

Influence of Residue Soil on the Properties of Fly Ash–Slag-Based Geopolymer Materials for 3D Printing

“…Ordinary Portland cement (OPC) is the most commonly used binder material, and its extraction and production processes are associated with high energy consumption and significant CO 2 emissions [ 12 , 13 , 14 ], exacerbating global warming issues. Therefore, in the quest to develop cleaner, greener, and more sustainable 3D printing materials, recent research trends have tended towards the use of low-carbon, green binder materials, in order to reduce cement use and carbon dioxide emissions [ 15 , 16 ]. Compared to OPC, geopolymers have been widely accepted as green binders due to their superior mechanical and durability properties [ 17 , 18 ].…”