Geosynthetic Tensile Creep Tester (20 kN) – QualiGTX™ TCT
The QualiGTX™ TCT is designed to investigate how geosynthetic reinforcement materials respond to prolonged tensile loading and how their strength changes over time. Unlike conventional tensile tests, which measure performance over a short period, creep testing reveals the gradual deformation that can eventually lead to material failure under sustained loads. This makes the instrument particularly important for evaluating geotextiles, geogrids, and other reinforcement products intended for long-term use in civil engineering structures.
To accommodate the extended duration of creep testing, the instrument features four independent testing stations, allowing four specimens to be evaluated concurrently under different loading conditions. This arrangement enables laboratories to establish creep behavior across multiple stress levels without completing each test individually. The system supports loads up to 20 kN, maintains load measurement accuracy within ±1%, and detects specimen displacement with a resolution of 0.03 mm.
The testing process is managed through an integrated control and measurement arrangement comprising a servo motor loading system, a data acquisition and processing unit, and a main structural frame. Microcomputer controls coordinate the application of load, monitor specimen deformation, and collect measurements automatically at predetermined intervals. Laboratories can also record measurements manually when an independent means of data verification is required. Time measurement accuracy of ±1% helps maintain the consistency of long-duration test results, particularly when measurements are used to develop creep curves and predict material performance over extended service periods.
Specimen accommodation is another important consideration in long-term creep evaluation. The QualiGTX™ TCT provides 800 mm of effective creep space, allowing sufficient travel for the initial gauge length and the progressive elongation of geosynthetic materials during testing. Its 350 mm effective test width accommodates wide geogrid specimens containing multiple ribs, rather than limiting evaluation to individual reinforcement sections. Two grip widths, 50 mm and 200 mm, are available to accommodate different specimen dimensions, including narrow strips and wide-width samples. These capabilities make the system suitable for geosynthetic production facilities, product certification laboratories, and geotechnical research institutions requiring dependable long-term tensile performance data.
Geosynthetic Tensile Creep Tester (20 kN) – QualiGTX™ TCT Applications
Long-term creep performance determines how much sustained tensile load a geosynthetic reinforcement material can safely withstand throughout the service life of a structure. The QualiGTX™ TCT supports engineering evaluations, material qualification, and research involving time-dependent deformation and strength retention.
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Reinforced Soil Wall and Slope Design: Establishes creep reduction factors used to convert short-term tensile strength into long-term design strength for reinforced soil structures.
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Geogrid Manufacturer Certification: Generates long-term creep performance data required by product approval programs and engineering design references before geogrids can be specified.
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Basal Reinforcement over Soft Ground: Evaluates reinforcement subjected to sustained tensile loading over extended periods while the underlying foundation undergoes consolidation.
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Landfill Sideslope and Veneer Reinforcement: Assesses geosynthetic materials supporting continuous loads in containment systems designed for long service periods after closure.
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Polymer and Product Development: Enables comparative evaluation of polyester, polypropylene, and polyethylene formulations, accounting for the substantial differences in their creep characteristics.
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Third-Party Approval and Certification Laboratories: Provides documented creep and creep rupture curves for technical assessments and client certification submissions.
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Bridge Abutment and Retaining Structure Design: Supplies long-term tensile performance information needed to evaluate reinforcement in permanent retaining and bridge support structures.
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Academic Research on Viscoelastic Behavior: Facilitates investigations into time-temperature superposition principles and accelerated creep testing techniques.
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Forensic Investigation of Long-Term Deformation: Helps determine whether movement observed in reinforced structures is associated with reinforcement creep or another underlying mechanism.
Standards
The QualiGTX™ TCT is designed to conduct geosynthetic tensile creep and creep rupture evaluations in accordance with the following internationally recognized test method:
- ISO 13431 – Geotextiles and Geotextile-Related Products: Determination of Tensile Creep and Creep Rupture Behaviour: Specifies the method for evaluating the time-dependent tensile deformation and rupture characteristics of geotextiles and related geosynthetic products under sustained loading.
Geosynthetic Tensile Creep Tester (20 kN) – QualiGTX™ TCT Key Features
The QualiGTX™ TCT combines simultaneous multi-specimen testing with precise load application, displacement monitoring, and time measurement to support reliable long-duration creep evaluations.
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Four Independent Test Stations: Accommodates four specimens simultaneously, allowing different load levels to be investigated in parallel and substantially reducing the overall duration of multi-level creep programs.
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20 kN Load Capacity: Supports tensile creep testing of high-strength reinforcement geogrids, woven geotextiles, and lower-strength geosynthetic materials using the same instrument.
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Servo Motor Loading System: Uses servo-controlled loading to apply the specified tensile force and maintain the required load throughout the test.
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±1% Load Accuracy: Maintains precise control of the applied load relative to the specimen's ultimate tensile strength, an important factor because even small load variations can significantly influence rupture time.
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0.03 mm Displacement Measurement: Detects small deformation increments required to establish the progression and slope of creep curves across successive logarithmic time intervals.
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±1% Time Measurement Accuracy: Provides consistent time tracking for long-term creep measurements and supports dependable extrapolation using a logarithmic time scale.
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800 mm Effective Creep Space: Provides sufficient specimen travel for the original gauge length and the substantial elongation that extensible reinforcement materials develop before rupture.
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350 mm Effective Test Width: Accommodates wide geogrid specimens across multiple longitudinal ribs, allowing evaluation beyond individual-rib samples.
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Selectable 50 mm and 200 mm Grips: Provides two gripping widths to accommodate narrow-strip and wide-width specimen configurations.
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Automatic Timed Data Logging: Records measurements according to programmed intervals throughout tests that may continue for thousands of hours. Manual data collection is also supported for independent verification.
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Microcomputer Process Control: Coordinates the loading sequence, measurement acquisition, and data processing across all four test stations through an integrated control system.
Theory and Method
Geosynthetic reinforcement materials made from polymers undergo gradual deformation when exposed to a sustained tensile force. Over time, their long molecular chains shift and rearrange, causing continued elongation even after the initial elastic deformation has occurred. This time-dependent response, known as viscoelastic creep, explains why short-term tensile strength alone cannot represent the load-bearing capacity of reinforcement over a design life of 100 years. When reinforced structures are designed using only short-term tensile properties, the reinforcement may experience excessive deformation or, under unfavorable conditions, rupture at loads that it can withstand during conventional laboratory tensile testing.
Tensile creep testing examines this behavior by maintaining a constant tensile force corresponding to a selected percentage of the specimen's ultimate tensile strength while continuously monitoring its developing strain. At relatively low load levels, deformation may gradually approach a stable value, producing a creep curve that describes the material's response over time. When higher loads are applied, the specimen may eventually fail, allowing the time to rupture to be established. Repeating the procedure at several load levels generates a series of relationships between applied tensile load and rupture time. For most reinforcement polymers, these results form an approximately linear relationship when plotted against logarithmic time. Extending this relationship to the intended design life provides an estimate of the creep-limited strength. Comparing short-term tensile strength with this value establishes the creep reduction factor used in long-term reinforcement design calculations.
The four-station configuration makes extended creep investigations considerably more practical by allowing multiple load levels to be evaluated concurrently. Since individual tests can continue for 1,000 hours or longer, conducting them sequentially on a single-station instrument could require several years to establish a complete creep relationship. The QualiGTX™ TCT addresses this limitation by testing four specimens in parallel.
Its 800 mm effective creep space provides the travel required for the specimen gauge length and the significant elongation that extensible geogrids can accumulate before failure. This helps ensure that testing can continue until specimen rupture rather than being interrupted by insufficient instrument travel. The 0.03 mm displacement resolution captures the small changes in elongation used to establish strain progression over successive logarithmic time intervals. These measurements are essential for determining the slope of the creep relationship and supporting reliable long-term strength extrapolation.
Geosynthetic Tensile Creep Tester (20 kN) - QualiGTX™ TCT Technical Specifications
| Parameter |
Specification |
| Test Methods |
Tensile creep, tensile creep rupture |
| Number of Test Stations |
4 |
| Maximum Load |
20 kN |
| Load Accuracy |
≤ ±1% |
| Displacement Measurement Accuracy |
0.03 mm |
| Time Measurement Error |
≤ ±1% |
| Effective Creep Space |
800 mm |
| Effective Test Width |
350 mm |
| Grip Width Options |
50 mm and 200 mm |
| Loading System |
Servo motor |
| Control and Acquisition |
Microcomputer control, automatic timed logging, manual collection available |
| Applicable Materials |
Geotextiles, geogrids, and geotextile-related reinforcement products |
| Dimensions (W × D × H) |
2900 × 650 × 1950 mm |
