Fly Ash Aluminous Cement Binder for Rapid Setting Backfill
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current self-compacting backfills with rapid setting capabilities often require high amounts of cement, leading to embankments that are difficult to re-excavate and have slow drainage, making it challenging to quickly return roads to traffic without damaging underlying networks.
Innovation Solution
A hydraulic binder composition comprising fly ash, aluminous cement, and hydrated lime, which sets rapidly and allows for easy re-excavation, even in non-draining environments, by acting as both a lubricant and binder, enabling rapid traffic resumption without the need for extensive drainage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a larger quantity of binder (more than 50 kg of cement per m3 of backfill) is used to achieve rapid setting, then the setting speed is improved, but the re-excavability deteriorates (leaves class 1 or 2)
Solution Approach 1:
The patent changes the chemical composition parameters of the binder by using a specific mix of fly ash (70-90%), aluminous cement (5-20%), and hydrated lime (0.05-15%). This parameter change allows the binder to set rapidly while maintaining low crushing strength for easy re-excavability, resolving the contradiction between setting speed and re-excavability.
Solution Approach 2:
The patent creates a composite binder material combining fly ash, aluminous cement, and hydrated lime in specific proportions. This composite material achieves both rapid setting properties and maintained re-excavability, overcoming the limitation of using pure cement which provides rapid setting but poor re-excavability.
2Productivity
If a larger quantity of binder is used to achieve rapid setting, then the setting speed is improved, but the time required for backfill to set deteriorates (remains 2-3 hours)
Solution Approach 1:
The patent modifies the chemical parameters of the binder system by incorporating aluminous cement and hydrated lime with fly ash, which accelerates the setting reaction. This parameter change reduces the setting time from 2-3 hours to under 1 hour, significantly improving productivity while reducing time loss.
Solution Approach 2:
The aluminous cement in the binder composition promotes accelerated chemical reactions that speed up the setting process. This acceleration mechanism reduces the setting time substantially, improving backfilling efficiency and minimizing road closure time.
3Strength
If drainage is used to improve bearing capacity, then the bearing capacity is improved, but the process speed deteriorates (drainage stage is slow)
Solution Approach 1:
The patent extracts the drainage step from the backfilling process by using a binder composition that achieves rapid setting and sufficient bearing capacity without requiring water drainage. This eliminates the slow drainage stage, maintaining bearing capacity improvement while significantly increasing process speed.
Solution Approach 2:
The binder composition is designed to preliminarily establish the necessary bearing capacity through rapid chemical setting, eliminating the need for subsequent drainage operations. This preliminary action achieves the same bearing capacity improvement as drainage would provide, but without the time penalty.
4Speed
If binder quantity is increased to achieve rapid setting, then the setting speed is improved, but the environmental adaptability deteriorates (only works in draining environments)
Solution Approach 1:
The binder composition is designed with multi-functionality to work effectively in both draining and non-draining environments. The combination of fly ash, aluminous cement, and hydrated lime provides setting acceleration and strength development that is independent of drainage conditions, expanding environmental adaptability while maintaining rapid setting capability.
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
The binder composition achieves rapid setting within 20-40 minutes, meets MAR 1 or 2 re-excavability criteria, and allows for quick road reopening without significant drainage, ensuring minimal disruption and network protection.
Implementation Method 1
the binder plays both the role of lubricant between the particles and/or grains of the granular composition composing the embankment and the role of binder between the particles by the phenomenon of hydraulic setting which is the origin of the solidification and therefore of the mechanical resistance of the embankment formed with the hydraulic binder composition according to the invention
Implementation Method 2
the binder plays both the role of lubricant between the particles and/or grains of the granular composition composing the embankment
Data Source
AI summary
A hydraulic binder composition intended to be used to form a self-compacting and re-excavatable backfill, said hydraulic binder composition comprising fly ash, aluminous cement, and hydrated lime, said hydraulic binder composition being intended to be mixed with a granulate composition and with water to form said self-compacting and re-excavatable backfill.