The Slab Load Test evaluates a concrete slab's actual performance by measuring maximum deflection under specified loads — a tool engineers reach for when doubts arise about an existing slab's safety, not during initial design.
When Is a Slab Load Test Needed?
The test may be required in cases such as:
- Low 28-day concrete compressive strength results and rejected Core test results.
- Irregular pours or influential Cold Joints.
- Cracks appearing due to loads exceeding the design loads.
- Fire exposure that damaged or degraded the concrete slab.
- Doubt about the slab's ability to safely carry the design loads.
How Is the Test Carried Out?
Asas Lab's team mounts digital displacement gauges beneath the slab on metal scaffolding at defined measurement points, then applies a distributed test load — typically neatly stacked cement bags representing the design load — while deflection readings are recorded at each loading stage.
What Does the Result Mean?
The recorded deflection is compared against the limits allowed by the structural code. If the slab stays within safe limits with no significant permanent deflection after the load is removed, it's considered able to safely carry its design loads. Exceeding those limits, or unrecoverable deflection, calls for deeper structural investigation and may require strengthening the slab.
Asas Lab offers Slab Load Testing as part of its engineering testing services, with a qualified technical team and calibrated measurement equipment, issuing a certified report with results and recommendations.