Calibration of Speedy Moisture Meter

 JOB NO. 1

CALIBRATON OF SPEEDY MOISTURE METER. Murtaza Abbas 2007-CIVIL-140 SECTION-D 9/9/2009

GEOTECHNICAL ENGINEERING LABORTARY. UNIVERSITY OF ENGINEERING AND TECONOLOGY, LAHORE.

CALIBRATION OF SPEEDY MOISTURE METER A speedy moisture meter is a handy instrument to determine the moisture content of soil stratum but it gives the value of moisture content in terms of  wet weight of the soil, wsp. Therefore it is important to convert this value for dry weight of soil solids, for the sake of accurate results. For quick determination of moisture content a calibration curve is drawn to compare values between the actual moisture content and the moisture content shown by the speedy moisture meter.

Apparatus: 1. 2. 3. 4.

Speedy Speedy moistu moisture re mete meter. r. Two Two stee steell bal balls ls.. Pans. Electr Electroni onic c balanc balance. e.

Procedure: 1- Weigh 200g of soil with an electronic balance. 2- Add water in soil equal to 5% of weight of soil. s oil.

3- Mix the water water until until a uniform uniform mixture mixture is attained attained.. 4- Place this this soil in oven oven to note the dry dry weight weight of soil, so that that we can carry out the process of calculating moisture content ‘w’ of soil. FOR SPEEDY MOISTURE METER: 5- Weigh 26g of the wet soil with the speedy moisture meter meter balance and and put it in the speedy moisture meter. 6- Check Check Zero error error on the moisture moisture meter meter.. 7- Now, add 2 scoops scoops of calcium calcium carbide carbide in the speedy speedy moisture moisture meter meter and follow it with the placing of steel balls (pulverize) inside the moisture meter. 8- Put the cap back back on the moisture moisture meter meter so that none of acetyl acetylene ene gas escapes. 9- Start shaking shaking and rotating rotating the moisture moisture meter meter simultane simultaneously ously.. As a result the dial under the meter will start moving.

10-Note the value when the dial stops moving. This is wsp expressed as a

percentage. 11-Repeat the same process with further addition a ddition of water (8%, 11%, 14%,17%, 20% )

OBSE OBS ERVATI RVA TIONS ONS AND A ND CALC C ALCULA ULATI TIONS ONS : Error in dial gauge of speedy moisture meter = 0.6 Weight of soil in apparatus = 26 gm Weight of calcium carbide (CaC 2) = 24 gm Dial gauge reading = 12.2 Corrected dial gauge reading = wsp = 12.2 - 0.6 = 11.6

Table 1.1

COMMENTS: Serial #

1

2

3

4

5

6

Moisture Content w’ %

5

8

11

14

17

20

Can No.

48

59

97

42

50

92

Empty weight W1 (gm)

13.72

15.62

14.06

15.98

14.03

14.05

Wet Wt.+

23.96

31.60

29.55

39.51

34.07

42.35

Oven dry wt. W3 (gm)

23.38

30.31

27.85

36.37

30.99

37.37

Moisture Content ‘w’ %

6.00

8.78

12.33

15.40

18.16

21.35

Speedy moisture meter reading ‘wsp’ %

5.6

7.8

11.6

13.4

16.8

25.2

Wt. of can W2 (gm)

1. When we use use speedy moistu moisture re meter meter in field, field, it could be a chance chance that it gives moisture moisture content more or less than the moisture content determined by any other method e.g. by oven drying method. 2. In this experim experiment ent we have have observed observed the value value of moisture moisture in percentage obtained by speedy s peedy moisture meter sometimes increase or sometimes decrease from the predetermined moisture. 3.  This is because of the fact that either the instrument is too old or it gives error in dial gauge reading. 4. Also due to availabi availability lity of only only one apparatus apparatus in lab we cannot cannot get much idea about that, but it fulfills the cause. REMEDIAL MEASURES: 1. There are two two ways of of getting getting better better results, results, i. If the apparatus apparatus is is old or or damaged, damaged, it it is bette betterr to replac replace e it with new one ii. Calibrate Calibrate it. it. Calibrati Calibration on can be be done from from some some good good laboratory of any institution. UNDERSTANDING:  This experiment helps us a lot in future life, if we will do some field  job and encounter some problem related to calibration, and then this performance of calibration through graph makes it easy for us to calibrate the apparatus in field.