HUMBOLDT H-4140 Geo Gauge

Humboldt H-4140 GeoGauge is an advanced soil compaction & material strength process control instrument that allows the construction of roads and highways. It is ideal for in-place QC of unbound materials for resilient modulus estimates, modulus measurements that correlate well with relative compaction, identifying structural anomalies, quantifying strength gain with time and obtaining precise measurements. Unlike density gauges, this GeoGauge can measure the load-bearing characteristics of compacted materials in situ. It can be used to estimate CBR and the results of plate load tests, laboratory R-Value, FWD or DCP quickly.

Working Mechanism:

• Switch On the GeoGauge.
• Prepare the testing surface.
• If necessary, enter target stiffness from a pre-defined, scrolling list via the display.
• Check the GeoGauge precision (daily).
• Ensure that the foot is properly seated.
• Take your measurements.
• Take the GeoGauge out of the test location.
• Examine the area and make sure you have good foot contact.
• Remove any soil that has become caked on the foot during testing.
• By pressing the "save" button, save the data.
• When finished, turn Off the GeoGauge to save battery power.
• Data can be transferred using an optional infrared interface.

Features:

• It dynamically measures in-place engineering properties such as structural layer stiffness, mN/m (milliNewton per metre) and material Young's Modulus.
• The unit includes a clock that records the time and date of each stiffness measurement.
• For effective QC / QA, the GeoGauge supports and directly links the in-place engineering properties of compacted materials with Mechanistic-Empirical design.
• Humboldt H-4140 allows reduced structural variability and maximum lift stiffness with minimal compaction effort.
• It allows uniform stress transmission and distribution from pavement to subgrade, which results in longer pavement life, lower maintenance costs and longer-lasting surface smoothness.
• It applies steady-state sinusoidal loads to the soil's surface and measures the resulting displacement, simulating real-world conditions.
• The unit comes in a transit case that has both a key lock and a combination lock. The factory set combination is '0-0-0'.

Standards and Approvals:

• ASTM D6758

Frequently Asked Questions:

Q. What is Young's Modulus?

A. It is the resistance of a material to changing shape in the direction of stress. It is the determination of material's strength.

Q. How to ensure that the GeoGauge is working properly?

A. If the mean stiffness is between -8.6 and -9.8 mN/m, the GeoGauge is working efficiently.

Q. How much data can this unit save?

A. Humboldt H-4140 will save data for 500 measurements (Operational Mode). Only the first 20 stored measurements will include the complex, frequency-dependent components of displayed data (Research Mode).

Q. How do you ensure proper seating?

A. Place the GeoGauge on the ground and hold the side or bottom of the gauge to rotate it (no more than half a revolution). You can now take the measurement. The seating is adequate if the Coefficient of Variation is less than 10% for repeated measurements at a single location.

Q. How do you reset the combination number?

A.

• Open the case. A lever is located at the back of the lock.
• Move this lever to the middle of the lock, hooking behind the change notch. Slide it sideways, then up.
• Turn the dials to the desired three-number combination.
• Return the change lever to its original position.
• Close the case securely and rotate one or more of the dials to lock.