Recycled Powder Workability in Mineral Binder Compositions
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Solution Overview
Problem
Current methods for recycling waste construction material, particularly demolition waste, fail to effectively improve the workability of mineral binder compositions containing recycled powder, leading to incomplete reuse and disposal challenges due to issues with flow and setting times in concrete and mortar applications.
Innovation Solution
Admixing workability improvers such as polycarboxylates, lignosulphonates, sugar acids, or sugars into mineral binder compositions with recycled powder to enhance initial flow and maintain slump flow over time, using methods like mechanical and chemical treatments to retrieve recycled powder from waste construction materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If recycled powder is added to mineral binder composition, then recycling efficiency is improved, but workability and slump flow are deteriorated
Solution Approach 1:
A surfactant is introduced as an intermediary substance between the recycled powder and the mineral binder. The surfactant mediates the interaction by adsorbing onto the recycled powder particles, modifying their surface properties and improving their compatibility with the binder matrix, thereby maintaining workability while enabling high recycling content
Solution Approach 2:
The chemical and physical parameters of the recycled powder are modified through surfactant treatment. The surfactant changes the surface charge, hydrophobicity, and dispersion characteristics of the recycled powder particles, transforming them from incompatible inclusions to well-integrated components that preserve fresh mixture workability
2Quantity of substance
If recycled powder is added to mineral binder composition, then material reuse is improved, but initial slump flow is reduced
Solution Approach 1:
The surfactant acts as a mediator that facilitates the dispersion of recycled powder particles in the fresh mixture. By reducing particle-particle aggregation and improving particle-binder adhesion, the surfactant enables high recycled powder content (up to 65 wt%) without significantly compromising the initial slump flow
Solution Approach 2:
The invention creates a composite system where surfactant-coated recycled powder particles are integrated into the mineral binder matrix. This composite approach allows the recycled powder to function as a functional filler rather than an inert additive, maintaining flow characteristics while achieving high material reuse
3Loss of energy
If recycled powder is added to mineral binder composition, then waste disposal cost is reduced, but setting time is prolonged
Solution Approach 1:
The surfactant treatment modifies the surface chemistry of recycled powder particles, which influences the hydration kinetics of the binder. The modified surface properties create a balance where the recycled powder continues to contribute to strength development while the setting time remains within acceptable ranges for construction applications
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Significantly increases the initial slump flow by at least 20% and maintains it for extended periods, ensuring workability and prolonged setting times suitable for practical applications, thereby improving the recycling efficiency of waste construction materials.
Implementation Method 1
Admixing workability improvers selected from the group consisting of polycarboxylates, lignosulphonates, sugar acids, sugars, or mixtures thereof
Data Source
AI summary
Methods to improve the workability of a mineral binder composition include at least one mineral binder and additionally recycled powder, said methods comprising the steps of providing at least one mineral binder, admixing recycled powder, admixing at least one workability improver selected from the group consisting of polycarboxylates, lignosulphonates, sugar acids, sugars, or mixtures thereof, and admixing water.