Hot-Mixed Asphalt Mixture Preparation with Segmented Mixing
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Solution Overview
Problem
Conventional hot-mixed asphalt mixture preparation methods ignore the lithology and surface area of aggregates, leading to uneven asphalt film thickness and compromised compaction and pavement performance.
Innovation Solution
A method involving separate preheating of asphalt and aggregates, followed by batch addition of coarse and fine aggregates based on the total work of adhesion ratio, with a mineral powder, to achieve uniform asphalt film distribution and improved mixture properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If all aggregates are added into a mixing pot at once, then the mixing process is simple and fast, but the asphalt film thickness becomes uneven and compaction effect deteriorates
Solution Approach 1:
The aggregate mixing process is segmented into multiple stages: first mixing coarse aggregates with asphalt, then adding fine aggregates in a second mixing stage. This segmentation allows different aggregate types to be coated with asphalt separately, ensuring uniform asphalt film thickness on each aggregate surface before final mixing, thereby resolving the contradiction between mixing speed and film uniformity.
Solution Approach 2:
Different aggregate types (coarse and fine aggregates) are treated differently in the mixing process. Coarse aggregates are mixed with asphalt first to form a uniform coating, then fine aggregates are added separately. This local differentiation ensures that each aggregate type receives appropriate asphalt coating based on its specific surface area and absorption characteristics, achieving uniform asphalt film thickness while maintaining efficient mixing.
2Device complexity
If aggregates of the same particle size are mixed together, then the mixing process is simplified, but asphalt film thickness varies due to lithology differences
Solution Approach 1:
The mixing process is segmented by aggregate type (coarse vs. fine aggregates) rather than mixing all aggregates uniformly. This segmentation allows separate optimization of the mixing process for each aggregate type, accounting for their different lithologies and surface areas, thereby achieving uniform asphalt film thickness without excessive process complexity.
Solution Approach 2:
The mixing process applies local quality by treating coarse and fine aggregates differently based on their specific properties. Coarse aggregates are mixed with asphalt first, then fine aggregates are added separately. This localized differentiation ensures that each aggregate type receives appropriate asphalt coating according to its lithology and surface area characteristics, achieving uniform film thickness while keeping the overall process manageable.
3Loss of time
If asphalt is added to all aggregates simultaneously, then the mixing time is reduced, but the compaction effect and pavement performance are compromised
Solution Approach 1:
The mixing process is segmented into sequential stages: first mixing coarse aggregates with asphalt, then adding fine aggregates in a second mixing stage. This segmentation ensures that asphalt has sufficient time to properly coat and bond with each aggregate type before the next stage begins, achieving uniform asphalt film thickness and optimal compaction effect without excessive mixing time.
Solution Approach 2:
Coarse aggregates are mixed with asphalt in advance before fine aggregates are added. This preliminary action allows the asphalt to fully coat the coarse aggregates and form strong bonds, ensuring proper compaction and pavement performance. The sequential addition of fine aggregates afterward maintains this preliminary coating effect while completing the overall mixing process efficiently.
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
This approach results in a hot-mixed asphalt mixture with enhanced compaction effect and pavement performance, reducing asphalt usage while maintaining excellent properties without increasing production costs, suitable for various surface structures.
Implementation Method 1
preheating asphalt and aggregates separately
Implementation Method 2
all the aggregates adsorb hot asphalt simultaneously
Implementation Method 3
the influence of the lithology and surface area (SA) of an aggregate on its ability to adsorb asphalt
Data Source
AI summary
The present invention provides a method for preparing a hot-mixed asphalt mixture, and relates to the technical field of road engineering. In the present invention, asphalt and aggregates are preheated separately, where the aggregates include coarse aggregates and fine aggregates; the coarse aggregates, part of the fine aggregates and asphalt that are preheated are subjected to a first mixing to obtain a first mixture; the remaining fine aggregates are added to the first mixture for a second mixing to obtain a second mixture; and a mineral powder is added to the second mixture for a third mixing, and discharging is conducted to obtain a hot-mixed asphalt mixture.