Static Cyclic Compression Test: Checklist and Procedures

Definition: Static cyclic compression test procedure for construction materials and components, guiding technicians through controlled axial load cycling, recovery measurements, and degradation evaluation while explicitly excluding tension and lateral actions.

What: Apply axial compression cycles; measure recovery and stiffness degradation.
Why: Quantify fatigue-like damage and residual strain under repeated loads.
How: Displacement-controlled cycles, calibrated sensors, clear acceptance tolerances.
Interactive, commentable, export, QR code: capture evidence and secure sign-offs.

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Checklist

Static cyclic compression test defines a controlled method to apply repeated axial compression to a specimen, capture recoveries, and evaluate stiffness degradation. Also called cyclic compressive loading or static cyclic loading, this protocol focuses on axial compression cycles only—tension and lateral actions are intentionally excluded. The checklist suits lab and site labs evaluating concrete, masonry units, elastomeric bearings, grout cubes, and similar materials. It reduces risks from misalignment, uncontrolled rates, drift, and data loss by prescribing calibrated equipment, displacement control, and evidence capture. Technicians gain consistent outcomes: recovery ratio, residual deformation, cycle-by-cycle stiffness, and qualitative damage. Supervisors get traceable documentation linked to project IDs, environmental conditions, and calibration certificates. Follow this step-by-step guide to set up the load frame, instrument the specimen, run pre-cycles, execute the full cyclic protocol, and complete post-test measurements and reporting. Use the interactive features to tick tasks, add comments and photos, and export PDF/Excel with a QR-secured audit trail.

Use displacement-controlled cycles with calibrated sensors to quantify immediate recovery, residual deformation, and stiffness loss. Control rate within ±10%, keep temperature near 20 ±2 °C, and verify alignment under a small preload to minimize eccentric effects.
Define a cycle protocol suited to the material: amplitude as a fraction of target compressive capacity or displacement, dwell times to capture creep/recovery, and a stable sampling rate. Pre-cycles seat the specimen and reveal setup issues before full loading.
Interactive online checklist with tick, comment, and export features secured by QR code.
Document all evidence for traceability: calibration certificates, environmental readings, configuration files, load–displacement plots, photographs of damage, and signed approvals. Archive raw data (.csv) and reports with consistent file names tied to the specimen ID and project.

Pre-Test Verification

1. Confirm test scope per approved project specifications and authority requirements; compression-only protocol (no tension/lateral). Verify lab conditions 20 ±2 °C, 40–70% RH; capture thermohygrometer photo and supervisor signature.
2. Verify universal testing machine compression capacity exceeds expected peak by ≥20%. Calibration certificate within 12 months; system accuracy ±1% of reading. Attach certificate PDF to test folder.
3. Check safety: guards in place, shields clear, emergency stop functional, pinch points marked. PPE worn (gloves, eyewear, safety shoes). Record checklist and photo of machine status panel.
4. Set up data acquisition with unique test ID; configure autosave every 5 s to local and network folders. Sync system clock (±2 s). Take a configuration screenshot.

Specimen Preparation & Identification

5. Inspect specimen for cracks, voids, or edge chipping >1 mm; reject if present beyond limits. Photograph all faces and label durable ID with marker; log material, batch, and curing age.
6. Prepare ends by machining or capping to achieve parallelism ≤0.02 mm and end perpendicularity ≤0.5°. Verify with straightedge and feeler gauges; record method and measurements with photos.
7. Measure diameter/width and height at three locations using calibrated calipers (0.01 mm resolution). Compute cross-sectional area; record values on data sheet and capture instrument display photo.
8. Weigh specimen to 0.1 g on a calibrated scale; compute density if required. Log serial number of scale and attach photo of reading.

Load Frame Setup & Alignment

9. Clean compression platens; remove debris and films. Verify flatness with feeler gauge: maximum gap ≤0.02 mm across contact area. Photograph platen condition.
10. Install spherical seat and center specimen using a centering ring or crosshair. Eccentricity ≤1 mm from axis; mark alignment on top/bottom and take positioning photos.
11. Apply preload of 0.5–1.0% expected peak load to seat specimen. Using two opposite dial indicators, confirm differential platen displacement ≤0.02 mm; record readings.
12. Set displacement limit stops to 110% of maximum planned amplitude to prevent overtravel. Perform a dry-run without specimen; save controller limit screenshot.

Instrumentation & Calibration

13. Mount axial LVDT/extensometer (range ≥110% expected displacement). Zero to ±0.01 mm at preload; record serial number and a zeroing photo.
14. Zero load cell after seating. Verify drift ≤0.5% full scale over 60 s. Confirm overall load accuracy ±1% of reading; capture stability plot screenshot.
15. Set sampling rate 10–50 Hz for static cycles; timestamp resolution ≤0.01 s. Save channel map (load, displacement, strain) as a configuration file linked to the test ID.

Cyclic Loading Execution

16. Select displacement control unless project requires load control; set rate 0.005–0.5 mm/s with controller tolerance ±10%. Record control mode and rate in the log.
17. Define protocol: 10–100 cycles between lower/upper bounds (e.g., 5–70% of target displacement or load). Dwell 5–30 s at peaks to capture recovery. Save profile screenshot.
18. Run three seating pre-cycles at 50% amplitude; monitor for sudden load drops >5% or unstable plots. If observed, stop and correct alignment; note findings with timestamps.
19. Execute full cycles; maintain temperature 20 ±2 °C. Observe live load–displacement hysteresis; pause if off-axis motion or platen tilt appears. Annotate anomalies and attach trend screenshots.

Post-Test Measurements & Evaluation

20. At final unload, hold 60 s and record immediate elastic recovery (mm). Calculate percent recovery relative to peak displacement; include calculation sheet and LVDT photo.
21. After 30 min rest, record residual deformation (permanent shortening). Compare to project limits; flag exceedances. Document with before/after readings and specimen photo.
22. Compute cycle stiffness (slope of near-linear segment) per cycle; plot stiffness versus cycle number. Flag ≥10% degradation. Photograph damage (crushing, barreling) and export signed PDF/Excel report.

Control Strategy and Cycle Design

For static cyclic compression, displacement control is typically preferred because it maintains cycle amplitudes even as stiffness changes. Choose lower and upper bounds as fractions of the expected compressive capacity or as absolute displacements based on material behavior. Dwell periods at peaks (5–30 s) help quantify immediate recovery and short-term creep. Keep rates slow and stable (0.005–0.5 mm/s) to avoid dynamic effects; this is a static protocol, not high-frequency fatigue. Pre-cycles at reduced amplitude seat the specimen and expose setup issues before committing to full cycles. Maintain temperature near 20 ±2 °C, as stiffness and recovery are temperature dependent. Acceptance cues include rate within ±10% of setpoint, no sudden load drops >5%, and repeatable hysteresis loops after stabilization. Example: elastomeric bearing pads often use displacement bounds; concrete cylinders often use load-derived bounds converted to displacement once stiffness is known.

Prefer displacement control for stability with changing stiffness.
Set slow rates to avoid dynamic effects and heating.
Use dwells to capture recovery and short-term creep.
Run pre-cycles to seat and validate setup.
Stabilize temperature near 20 ±2 °C for consistency.

Alignment, Seating, and Sensing

Misalignment biases results by introducing unintended bending, which inflates apparent degradation. Use a clean, flat platen pair and a spherical seat to accommodate minor angular mismatch. Center the specimen carefully; mark axes on both faces. Under a small preload (0.5–1.0% of peak), check opposite-side dial indicators; differential displacement should be ≤0.02 mm before proceeding. Mount an axial LVDT or extensometer with range exceeding the planned amplitude and zero within ±0.01 mm. Verify the load cell’s stability (drift ≤0.5% FS over 60 s) and overall accuracy (±1% of reading). Configure a sampling rate of 10–50 Hz and confirm synchronized timestamps. In one precast plant example, correcting a 1.5 mm eccentricity eliminated asymmetric loops and cut apparent stiffness loss from 18% to 6%, revealing the true material response.

Clean platens and verify flatness with feeler gauges.
Center with rings and confirm with dial indicators.
Zero sensors precisely and record serial numbers.
Check load cell drift and accuracy before testing.

Measuring Recovery and Degradation

After the final unload, hold for about 60 s to capture immediate elastic recovery, then record residual deformation after a 30-minute rest. Evaluate cycle-by-cycle stiffness by calculating the slope of the near-linear segment of each loading branch. Plot stiffness versus cycle number; a downward trend indicates degradation. The hysteresis loop area reflects energy dissipation, which may increase as microcracking or material softening progresses. Establish project-specific thresholds; a common reporting cue is flagging when stiffness reduction exceeds 10% from stabilized early-cycle values. Photograph visible damage such as end crushing, barreling, and cracking, including a scale in each image. Export raw data, plots, and a summary table showing recovery ratio, residual deformation, and stiffness loss for transparent review.

Hold after unload to capture elastic recovery.
Measure residual deformation after a timed rest.
Compute stiffness per cycle and plot trends.
Flag significant stiffness reduction for review.
Photograph damage with a physical scale.

How to Use This Static Cyclic Compression Test Checklist

Preparation: Gather a calibrated compression frame with platens and spherical seat, axial LVDT/extensometer, dial indicators, thermohygrometer, calipers/micrometer, scale, PPE, and a PC with data acquisition. Confirm project specifications and set a unique test ID before opening the checklist.
Using the Interactive Checklist: Start interactive mode, tick items as completed, and add time-stamped comments with photos or screenshots for evidence. If working offline, scan the QR to preload the form; later, sync and export the complete log to PDF/Excel.
Sign-Off: Capture digital signatures from technician and witness, lock the record, and distribute the report to stakeholders. Archive raw data, configuration files, and the signed PDF/Excel in the project folder; verify QR authentication for future audits.

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Leon Dubois LabChefLeon

Jan 18, 2026

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FAQ

Question: How many cycles should I run in a static cyclic compression test?

It depends on the material and project goals. For seating and baseline trends, 10–20 cycles are common. For degradation studies, 50–100 cycles may be specified. Choose bounds that avoid catastrophic failure, include dwells for recovery measurement, and stop early if instability, platen tilt, or unsafe conditions occur.

Question: Should I use load control or displacement control for cyclic compression?

Use displacement control for most static cyclic compression tests because it maintains amplitude as stiffness changes. Load control can mask softening and cause overshoot when stiffness drops. If project documents mandate load control, set conservative ramp rates, monitor displacement closely, and enforce overtravel limits to protect the specimen and machine.

Question: What indicates significant degradation during cyclic compression?

Track cycle-by-cycle stiffness and hysteresis loops. A consistent downward stiffness trend, expanding loop area, audible cracking, or visible end crushing are warning signs. Many projects flag when stiffness drops by 10% relative to stabilized early cycles. Document with plots, photos, and notes, and consult the engineer if thresholds are exceeded.

Question: How do I measure recovery and residual deformation correctly?

After the final unload, hold for about 60 seconds and record the immediate elastic recovery from the displacement transducer. Allow a timed rest (e.g., 30 minutes), then record permanent shortening as residual deformation. Keep temperature stable, avoid touching gauges, and log both values with timestamps and sensor photos.