1. Infrared Thermometer Luke M. Snell Concrete Industry Management Del E. Webb School of Construction Arizona State University Tempe Arizona

2. Traditional Approx of Temperature  Steel Temperature:. Dull Red Color- 550 C. Yellow Hot Color- 1150 C. White Hot Color- 1500 C

3. Emissivity Theory Used for Infrared Thermometer Infra-red

4. How IR Thermometer Works  Emitted Energy indicates the temperature of the object.  When IR thermometer senses the energy and converts to temperature

6. Product Description  Temperature range : -18 to 275 C  Accuracy: ± 2%, or ± 2°C whichever is greater  Response time: 500mSec  Ambient operating range: 0 to 50 C  Power: 9V alkaline or NiCd Battery included  Temperature display: C or F, selectable

7. Limitations  Measures only surface temperature,not the internal temperature  Can not shoot through windows  Laser Warning- need to be careful  Obstruction – smoke and dust particles

8. Application in Concrete Construction IR thermometer can: IR thermometer can:  Measure forms and reinforcement temperatures prior to placement (Less than 50 C)  Estimate concrete temperatures during placement (4 to 30 C).

9. Application in Concrete Construction IR Thermometer can:  Measure temperature of soil/base ( must be above freezing)  Monitor curing environment for first 7 days (should be maintained above 4C)

11. Temperature control Temperature control

12. Temperature control using IT  Materials and Mixture temperatures  Placement temperature  Temperatures maintained during curing

19. Temperature (C) Curing temperatures graph (C) Disco nnected time Time (hour)

20. T= 0.22 (TaMa + TcMc) + TwMw 0.22 (Ma + Mc) = Mw T = temperature of concrete, C Ta,Tc,Tw = temperature of aggregate, cement, water, C cement, water, C Ma,Mc,Mw = Mass (weight) of material in mixture, kg

21. EXAMPLE: Mixture, kg per cubic meter Mixture, kg per cubic meter Aggregates, 1839 kg @ 27C Aggregates, 1839 kg @ 27C Cement, 335 kg @ 66 C Cement, 335 kg @ 66 C Water, 123 kg @ 27C Water, 123 kg @ 27C Temperature of Concrete = 31.8C Need to chill water to 17C if concrete temperature is required to be less than 30C

22. Using IR in Mongolia  Water heated to 56 C  Fine aggregates - 18 C  Coarse aggregates - 19 C  Bags of cement - 19 C  Calculated temperature 4 C  IR temperature 1C

23. Where do you measure temperature with IR? Research project – measure concrete at :  Forms, wheel barrows or buggies  Revolving drum  Chute

24. Chutes provide accurate temperatures

25. Conclusion  IR thermometer can be used by the contractor to monitor the temperature of the concrete.  IR thermometers to determine if adequate curing of the concrete is achieved in hot /cold weather construction.