Work

Study on Alkali-Activated Slag Mortar Based on Co-Modified Recycled Fine Aggregate with Nano-SiO2 and Sodium Silicate Integrating Waste Liquid Recycling

Year: 2025

Type: article

Abstract: Critically important for both resource recovery from construction and demolition waste (C&DW) and for furthering sustainable development is the application of recycled fine aggregate (RFA). However, widespread utilization of RFA is constrained by the high porosity and microcracks inherent in the mortar adhered to its surface. In this investigation, RFA underwent modification using a nano-SiO2-sodium silicate mixed solution (NMS) to ameliorate the characteristics of the adhered mortar, thereby enhancing the performance of the subsequently prepared alkali-activated slag recycled fine aggregate mortar (AASRM). Concurrently, the recycled NMS (RNMS), originating from the modification process, was employed as a source of sodium silicate within the alkali activator. The influence of this recycled solution on AASRM performance, alongside associated economic and environmental benefits, was also evaluated. Experimental configurations included a control group (NM), MRs groups incorporating varying proportions of modified RFA (MRFA), and RMRs groups utilizing both MRFA and RNMS. Mortar specimen evaluations encompassed fluidity, capillary water absorption, compressive strength, and drying shrinkage, complemented by microstructural analysis. Significant improvements in the mechanical properties and durability of AASRMs were found to result from MRFA incorporation, which also refined the microstructure of the interfacial transition zone (ITZ). Furthermore, satisfactory mortar performance was maintainable through RNMS utilization. Economic and environmental assessments indicated that the application of RNMS can effectively curtail material costs and embodied carbon, signifying enhanced sustainability.

Source: Materials

DOI: 10.3390/ma18214889

Authors: Qiushi Su, Changbai Wang, Jimin Liu, Qinghua Liu

Institution: Anhui University of Science and Technology

Language: English

Topic: Recycled Aggregate Concrete Performance

Subfield: Building and Construction

Field: Engineering

Domain: Physical Sciences

SDG: Responsible consumption and production

Open Access status: gold

Estimated APC paid: $3,137