Frost Heave Testing methods using a Customized Test Chamber

frost heave testing chamber

What is Frost Heaving

 

Frost heaving (or frost heave) is a natural phenomena through which, in freezing conditions, soil swells up, as temperatures penetrate into it and ice grows upwards.

 

The ice crystals growth is restrained by the soil but that is not enough to contrast the formation of lenses within the soil that bind together with the latter and turn into a strong solid block that heaves the ground.

 

Normally the strength increases as the temperature is lowered.

 

This eventually damage roads and buildings, according to the type of soil and its moisture content.

 

Leading researchers such as Konrad, Morgenstern and Penner have studied frost heaving through various laboratory test methods in order to closely analyze the phenomenon.

 

Over time, some of the most important research centers around the world have proposed standardized test methods for research laboratories.

 

This is to guide them to better analyze the characteristics of frost heaving.

 

The references are the following:

 

  • TRRL (Transport and Road Research Laboratory) in the UK
  • ASTM International (American Society for Testing and Materials) in the USA (ASTM D5918)
  • JGS (Japan Geotechnical Society) in Japan (JGS 0172)

 

How to Simulate Frost Heaving

 

Preventing the process is extremely important but not easy.

 

An important customer of ours informed us about the difficulty in performing this type of test because of the unavailability on the market of a machine that could concretely verify the phenomenon.

 

That is why at FDM we developed a machine that could automatically perform the frost heave testing, simulating real environmental conditions.

 

The FDM SRU Frost heave chamber (FHU812)  was developed according to the according to the British standard BS 812-214.

 

It is composed by two different parts: a temperature- controlled part and a second environment where all the power and control components for the machine functioning are contained.

 

The temperature-controlled environment is divided into two tanks:

 

  1. A lower tank containing water at 4°C
  2. An upper tank containing refrigerated air at -17°C.

 

The tanks are independent from each other:

 

In between the tanks there is an intermediate cradle and a wooden support containing the samples to be tested.

 

The chamber also comes complete with a datum reference frame and 9 brass bars.

 

The 9 bars correspond to the 9 specimens that make the brass bars rise by capillary freezing.

 

Frost Heave Testing

fig1. FHU812 Testing chamber for frost heaving – composition 

 

How the SRU Machine Works

 

How does this machine work?

 

Exactly as a simulation of the natural phenomena, thus imitating the freezing of the soil.

 

The water from the temperature-controlled environment rises and freezes so to raise the bars.

The operator should measure every 24h how much bars raised. Measuring the lifting of each bar will then mean measuring the lifting of each sample.

 

The machine is equipped with a touch screen that automates the test as much as possible.

 

The user must load the chamber with the samples, install the reference frame, insert the brass rods and then start the test with a button on the touch screen.

 

The machine will take care of the rest by advising the user whenever it is necessary to check the heaving.

 

At the end of the test it is possible to remove the USB key and download on the PC all data from the eleven probes installed in the test volume onto a PC.

frost heave testing chamber

How we Facilitate your Tests

 

In FDM we are constantly looking for solutions to improve environmental tests in order to facilitate scientific researchers with efficient, reliable and above all customized machines for every type of use.

 

With this specific project, we were able to help a researcher who needed to simplify his testing process.

 

The operator revealed to us that the results were optimal.

 

The SRU has accelerated our client’s study processes by 60%, compared to its previous methods, and allowed it to obtain more reliable values.

 

In FDM we care about the needs of every customer, we listen to all requests and we try to meet all your testing requirements, even if it is a single customized machine.

 

By contacting FDM you will have immediate answers on feasibility and costs for your projects, with maximum transparency, professionalism and will to solve your problem.