Asphalt Shear Testing Device with Adjustable Steel Socket and Insert
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Solution Overview
Problem
Current methods for measuring shear properties of asphalt mixtures are inaccurate, require expensive equipment, and introduce variables such as glue quality and incorrect load direction, limiting their ability to predict permanent deformations in roadways effectively.
Innovation Solution
A device equipped with a steel socket and insert system that allows for adjustable clearance and dual-sided fixation of specimens, enabling testing in Universal Testing Machines (UTMs) with temperature control and flexible washers, which simulates in-situ loading conditions without the need for bonding, reducing costs and variability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the Superpave Shear Tester (SST) is used to measure shear properties, then measurement accuracy is improved, but equipment cost and complexity increase significantly
Solution Approach 1:
The device segments the specimen fixation system into separate components: a socket with inner flange for support and an insert with washer for loading application. This segmentation eliminates the need for complex glued joints while maintaining measurement accuracy, directly addressing the contradiction between precision and complexity.
Solution Approach 2:
The steel insert with washer acts as an intermediary element between the loading mechanism and the asphalt specimen. This intermediary enables accurate shear property measurement without requiring complex bonding procedures, resolving the contradiction by simplifying the device while maintaining precision.
2Reliability
If glue is used to fix the specimen to steel bases, then specimen fixation is achieved, but measurement variability and cost increase due to glue quality variations
Solution Approach 1:
The invention extracts the problematic glue component from the fixation system and replaces it with mechanical fixation using the socket's inner flange and the insert with washer. This eliminates the source of measurement variability while maintaining reliable specimen fixation.
Solution Approach 2:
The steel insert with washer serves as a simple, replaceable component that provides consistent mechanical fixation without the variability of adhesive bonding. This simple component replaces the complex glue application process, improving both reliability and measurement precision.
3Measurement precision
If the SST equipment is used for shear tension measurement, then accurate shear properties are obtained, but testing time and cost increase
Solution Approach 1:
The socket is pre-equipped with the inner flange and the insert with washer, creating a ready-to-use fixation system. This preliminary preparation eliminates time-consuming glue application and curing steps, reducing testing time while maintaining measurement accuracy.
Solution Approach 2:
The simple steel insert with washer replaces complex glued joints, enabling quick specimen changes and testing. This simple component allows for rapid setup and teardown, significantly reducing the time loss associated with SST equipment while maintaining precision.
4Ease of operation
If empirical test methods are used to predict permanent deformations, then testing simplicity is maintained, but prediction accuracy and applicability to design calculations are insufficient
Solution Approach 1:
The device provides universal applicability for both simple laboratory testing and accurate prediction of permanent deformations in roadway design. The mechanical fixation system enables straightforward operation while the precise measurement capability supports design calculations, bridging the gap between simplicity and accuracy.
Data Source
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AI summary
A device for measuring shear properties of asphalt mixtures containing a machine for testing the material strength, especially for tests of tensile, compression, flexural and shear strengths, equipped with an operational frame, fixing elements and driving mechanism. It consists of a steel socket (9) equipped at its bottom and/or its top edge with an inner flange (1) to accommodate the testing specimen (4), which is equipped with a central open hole in it, and it also contains a steel insert (2) that can be inserted into the open hole in the testing specimen (4), the steel insert (2) is equipped at it end at the top edge of the steel socket (9) and/or at its end at the bottom of the steel socket (9) with a rim (7), while the size of the clearance between the inner flange (1) and the rim (7) can be adjusted from 5 to 60 mm, and the steel insert (2) is equipped with elements for fixing to the clamping elements (3) of the testing device, and to the steel insert (2) are connected the measuring probes (5).