Technical reports: Liquid presence sensing

Cement Curing

At LAIIER we have carried out a series of tests for our Severn sensors to show their performance for a range of liquids and setups. Here we present a technical report for the Severn sensor when in contact with curing cement.

Cement curing

Measuring the response of the Severn sensor when in contact with curing cement. The concrete curing process has multiple stages such as the initial setting period or the main curing period so this test will see whether the Severn sensor can detect these key changes.

Procedure

Setup for measuring cement curing

The Severn sensor was adhered to the bottom of a shallow tray and around 750 g of cementitious adhesive was poured on top of the sensor. The sensor was connected to the Severn board to collect serial readings over the course of 6 days. Readings were taken every 30 seconds.

The experiment was set up indoors with a temperature of around 18°C and 79% humidity.

Results and findings

  • As seen on the graph, cement curing has a distinctive ‘initial curing’ peak before the main curing slope.
  • During the main curing period, sensor reading gradually increases as the cement becomes less conductive due to the internal water evaporating.
  • The Severn sensor was still adhered to the cement block at the end of the experiment meaning that readings have been from the cement surface at all times and not from peeling off.
Graph showing the curing of cement on the Severn sensor

Conclusion

The Severn sensor can detect the two main stages of cement curing: the initial setting period and the main curing period over the tested six days. These results concur with how water theoretically leaves the cement mixture as it cures.