A Light Weight Deflectometer (LWD) is a testing device that is portable and non-destructive, primarily used in geotechnical and pavement engineering. It is used to assess the structural properties and compaction of soils and pavements.

By measuring the deflection or deformation of a surface subjected to a known force, providing valuable information about the stiffness and load-bearing capacity of said material being tested.

The equipment used for LWD testing typically includes the LWD device itself, a load plate, a measurement system (e.g., sensors and data recording equipment), and a display for real-time results. The specific equipment may vary depending on the manufacturer and model of the LWD system being used.

How can LWD be used?

Soil compaction: This testing device is commonly used to assess the soil compaction rate during the construction stage of a project. By measuring the deflection of the soil surface when subjected to a load, engineers and geo technicians can determine the soil’s stiffness, which is important when it comes to proper compaction.

Pavement Quality: LWD can be utilised in pavement engineering to evaluate the structural integrity and longevity of road surfaces. It does this through measuring the deflection of the pavement under load, providing further insight into its condition and load-bearing capacity.

 What are the benefits of LWD testing?

Portability: LWDs are compact testing devices, which means they are easy to transport. This allows for on-site testing nationwide.

Rapid Results: LWDs provide geo technicians and engineers with rapid results, giving real-time assessments of soil and pavement conditions. This allows for proactive decisions to be made when it comes to construction or maintenance decisions.

Quality Control: LWD testing doesn’t damage the tested materials or structures, which is ideal for quality control during concrete or pavement investigations.

Cost efficient: Due to the rapid results that the LWD testing gives, the testing method can assist with optimising compaction efforts, which not only reduces the need for costly rework and ensures that materials for a project are used appropriately and efficiently.

Data Accuracy: LWDs have been designed to provide accurate deflection measurements, which contributes to reliable results.

Using LWDs in Soil Testing

LWD are typically used to assess the compaction of materials such as backfill materials, subgrade soils and embankments. LWD equipment consists of a load plate that is placed on the surface of the soil. From here, force is applied to the plate, and the LWD will measure the deflection. The deflection data is used to calculate the stiffness of the soil and will allow geo technicians and engineers to assess whether or not the soil meets compaction specifications.

Using LWDs in Level 1 Site Supervision

Level 1 Site Supervision and Testing refers to the quality control and assurance activities that take place during construction. When utilising an LWD for soil compaction testing, a Level 1 supervisor will oversee the proper use of the equipment. Typically, LWDs are operated by trained technicians, who will follow the established protocols for testing and recording results.

Using LWDs in Pavement Investigation

When it comes to Pavement Investigations, LWDs are used to evaluate the structural condition of roads, runways, and other paved surfaces.

When testing pavements, the LWD is placed on the pavement, and a load is applied to the device. The deflection measurement helps geo technicians and engineers assists with the pavement’s stiffness and load-bearing capacity, which is crucial information for pavement maintenance and rehabilitation project planning.

Do you have a project that requires Light Weight Deflectometer (LWD) testing?

For more information about our Light Weight Deflectometer (LWD) testing, contact our friendly team here, or request a quote here.