Category: Monitoring

VAKKA are sensors that wirelessly monitors the environmental conditions within the concrete as it hardens. The patent-pending environmental chamber is unique to the VAKKA system and allows for faster and more accurate readings. It quickly equalizes the surrounding environment allowing precise measurements to be recorded within minutes of pouring your concrete.

The free mobile app and cloud service empowers the user’s team to make faster and more confident decisions. The data can be downloaded to the app at any time when a connected device is within the 3-4 m range of the sensor and is instantly uploaded to the cloud where it is shared with the team. The app estimates the compressive strength by using the user defined maturity curve and allows instant access to the temperature and relative humidity readings, plotting data, and reports.

With the VAKKA sensors, the traditional method of braking cylinders is improved in accuracy and project cost savings by reflecting better the concrete strength gain in real-time. On the other hand, by knowing the up-to-date level of relative humidity of in-place concrete, the timing in which floor coverings are installed, such as resilient flooring, wood, epoxy or polymer-based coatings, can be optimized.

Maturity sensors.

• Estimating the compressive strength at an early age using a user defined strength-maturity relationship.
• Timing of pullout testing with LOK-TEST for early-age strength measurement.
• Evaluating the effective in-place curing temperature
• Timing the surface treatment on floor slabs.
• Monitoring water penetration in concrete

Maturity sensors

• Free mobile App for Android and IOS devices
• Wireless technology
• Easy installation and activation
• Accurate real-time data display of relative humidity and temperature
• Normalizes to ambient conditions within minutes of placement
• Long storage life with external magnetic activation
• Rugged, crush proof and waterproof design
• Full reporting
• Cloud data storage for team access to projects from any location
• Maturity methods: ASTM C1074 Nurse/Saul and Arrhenius
• Measurement interval: 30 min (fixed)
• Maximum data collection: 4,000 data points (60 days)
• Operational battery life: > 4 months (active)
• Storage battery life: 10 years (unactive)
• Temperature accuracy: +/- 0.3 ^oC
• H. accuracy:  +/-2%
• Embedment depth: 1 m or 3 m probe available for VAKKA-Tx/HTx sensors
• Attachment: Galvanized tie-wires

 Maturity sensors.

VAKKA Ordering Numbers

• Technical datasheet

ASTM C1074 -Standard Practice for Estimating Concrete Strength by the Maturity Method.

ASTM F2170 -Standard Test Method for Determining Relative Humidity in Concrete Floor Slabs Using in situ Probes.

The COMA-Meter (COncrete MAturity-Meter) is used to measure the maturity of newly cast concrete at a depth of 80 mm from the surface.
A glass capillary tube contains a special liquid for which the rate of evaporation varies with temperature according to the Arrhenius equation that is used to determine maturity of concrete from its temperature history. After the concrete is cast, the COMA-Meter is pushed into into the fresh concrete and the liquid in the capillary tube will evaporate at a rate determined by the temperature and time. The level of the liquid, readable on the scale, measures the maturity of the concrete stated in M20 units, which is the number of equivalent days of curing at 20 ºC.

• Estimating the compressive strength at an early age using a pre-established strength-maturity relationship
• Timing of pullout testing with LOK-TEST (consult Technical Data Sheet) for early-age strength measurement
• Evaluating the effective in-place curing temperature.

• Measuring ranges:
  • COMA-5 = 0 to 5 M₂₀ days
  • COMA-14 = 0 to 14 M₂₀ days
• Precision: ±0.1 M₂₀ days
• Accuracy: ±5 % compared with maturity values calculated from direct temperature readings
• Activation energy, E ≈ 40 kJ/mol.

Parts List

• Technical datasheet

No standards available.