Red Mud UHPC Accelerates Setting and Strength
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Solution Overview
Problem
Existing red mud recycling techniques face challenges such as complex dealkalization processes, alkali resistance, and uncertain radioactivity risks, which hinder efficient recycling and lead to environmental pollution.
Innovation Solution
An early-strength and quick-setting ultra-high performance concrete (UHPC) is developed by incorporating red mud as an early-strength agent at a high amount, along with silica fume, cement, quartz sand, water-reducing agent, water, and steel fiber, to create a composition that accelerates setting and strengthens the concrete while reducing alkali and radioactivity risks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If red mud is added as an early-strength agent in large amounts to UHPC, then setting time is significantly shortened and early-strength development is promoted, but alkali dissolution and radioactivity risks increase
Solution Approach 1:
The patent converts the harmful high alkalinity of red mud into a beneficial effect by utilizing it to accelerate cement hydration and promote early strength development. The alkali in red mud, which normally causes environmental problems, is transformed into a catalyst for rapid setting and strength gain in the UHPC system.
Solution Approach 2:
The patent optimizes the content of red mud within a specific range (110-180 parts by mass) to achieve the desired balance between quick-setting effect and performance maintenance. By precisely controlling the red mud content and particle size distribution (0.01-0.075 mm), the patent maximizes early strength while minimizing adverse effects.
2Strength
If red mud content is low (less than 150 kg/m3), then alkali supply is insufficient leading to limited early strength effect, but if red mud content is high, then quick-setting effect is achieved but concrete performance deteriorates
Solution Approach 1:
The patent determines the optimal red mud content range of 110-180 parts by mass, which provides sufficient alkali for accelerated hydration while preventing performance deterioration. This precise parameter optimization resolves the contradiction between achieving quick-setting effect and maintaining concrete reliability.
Solution Approach 2:
The patent creates a composite system combining red mud with silica fume (70-80 parts), cement (130-290 parts), and other materials. This composite approach allows the benefits of red mud's quick-setting effect to be realized while the other components compensate for potential performance losses and ensure overall concrete reliability.
3Ease of repair
If red mud is recycled through traditional methods (adsorbents, metal extraction, cement production), then red mud utilization is achieved, but dealkalization pretreatment is required increasing cost and difficulty
Solution Approach 1:
The patent eliminates the need for dealkalization pretreatment by directly utilizing the high alkalinity of red mud as a beneficial component in UHPC. Instead of removing or neutralizing the alkali through complex pretreatment processes, the patent harnesses it to accelerate cement hydration, thereby simplifying the recycling process while maintaining product quality.
Solution Approach 2:
The patent enables red mud to serve multiple functions simultaneously: it acts as a filler, an early-strength agent, and a setting accelerator in the UHPC system. This multi-functionality eliminates the need for separate dealkalization and treatment steps required by traditional recycling methods, significantly simplifying the overall process.
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 UHPC achieves a significant reduction in setting time, enhances early-strength development, and improves durability, while minimizing environmental pollution and radioactivity risks, thus enabling safe and efficient recycling of red mud.
Implementation Method 1
the high alkalinity of red mud could accelerate the hydration of cement and promote the setting hardening and early strength development of concrete
Implementation Method 2
the red mud has a low particle size (being between the silica fume and the cement), and thus could also provide a nucleation site for hydration products to accelerate the hydration
Data Source
AI summary
Provided are early-strength and quick-setting ultra-high performance concrete (UHPC), and a preparation method and use thereof. The early-strength and quick-setting UHPC includes, in parts by mass: 110 parts to 180 parts of a red mud, 70 parts to 80 parts of a silica fume, 130 parts to 290 parts of a cement, 400 parts to 500 parts of a quartz sand, 10 parts to 15 parts of a water-reducing agent, 80 parts to 100 parts of water, and 50 parts to 75 parts of a steel fiber. The preparation method includes: subjecting the silica fume, the cement, the quartz sand, and the red mud to first mixing to obtain a first premix; subjecting the first premix, the water, and the water-reducing agent to second mixing to obtain a second premix; and subjecting the second premix and the steel fiber to third mixing to obtain the early-strength and quick-setting UHPC.