yusuf's chloride analysis test results

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Chloride analysis test results

18 No. concrete cores were delivered for testing for chlorides. The cores were

numbered as follows: 1A, 1B, 2A, 2B, 3A, 3B, 4A, 4B, 5A, 5B, 6A, 6B, 7A, 7B, 8A,

8B, 9A and 9B. The chloride profiles were determined up to depths of 40 mm into theconcrete.

Assumpt ions

Density of concrete: 2500kg/m3

Sample preparation

All the concrete cores were sliced into two equal halves. One of the two halves from

each concrete core was further sliced into 10 mm thick slices up to a depth of 40 mm

into the concrete core. The specimens were cut with a cutter under minimum wetting

conditions. Thereafter, the specimens were oven dried for 3 days at 50 degree

Celsius.

Testing Methodology:

1. The oven dried specimens were then crushed into powder using a crusher.

2. The crushed powder was put in marked transparent plastic bags in preparation for

chloride analysis tests.

3. The chloride tests were done using a potentiometric titrator (Mettler Toledo DL50).

The chloride analysis results are summarized in the Tables 1 - 18 on the following

pages. The concentration of the chlorides was calculated using a binder content of

420 kg/m3.

Table 1: Chloride analysis results for core 1A

Core ID Depth from surface

(mm)

Chloride Concentration

(% by mass of concrete)

Chloride concentration

(% by mass of cement)

1A 5 0.258 1.54

15 0.161 0.96

25 0.060 0.36

35 0.053 0.32



A diagrammatic summary of Table 1 is shown in Figure 1.

Figure 1: Chloride profile for core 1A

Table 2: Chloride analysis results for core 1B


(mm)





1B 5 0.218 1.30

15 0.151 0.90

25 0.050 0.30

35 0.047 0.28




Figure 2: Chloride profile for core1B



(mm)





2A 5 0.288 1.72

15 0.102 0.61

25 0.051 0.30

35 0.044 0.26







(mm)





2B 5 0.235 1.40

15 0.263 1.56

25 0.055 0.33

35 0.046 0.28




Figure 4: Chloride profile for core 2B



(mm)





3A 5 0.147 0.87

15 0.277 1.65

25 0.196 1.17

35 0.095 0.56







(mm)





3B 5 0.183 1.09

15 0.294 1.75

25 0.193 1.15

35 0.082 0.49







(mm)





4A 5 0.218 1.30

15 0.256 1.52

25 0.203 1.21

35 0.118 0.70







(mm)





4B 5 0.189 1.13

15 0.194 1.15

25 0.164 0.97

35 0.109 0.65







(mm)





5A 5 0.355 2.11

15 0.456 2.72

25 0.228 1.35

35 0.219 1.30







(mm)





5B 5 0.257 1.53

15 0.262 1.56

25 0.378 2.25

35 0.197 1.18







(mm)

Chloride Concentration (% by

mass of concrete)

Chloride

concentration (%

by mass of

cement)

6A 5 0.264 1.57

15 0.339 2.01

25 0.210 1.25

35 0.179 1.06






Core ID Depth from surface (mm) Chloride Concentration


Chloride

concentration (%

by mass of

cement)

6B 5 0.322 1.92

15 0.339 2.02

25 0.239 1.42

35 0.201 1.20







(mm)





7A 5 0.562 3.35

15 0.273 1.63

25 0.061 0.36

35 0.051 0.30







(mm)





7B 5 0.775 4.61

15 0.557 3.32

25 0.285 1.70

35 0.150 0.89







(mm)





8A 5 0.342 2.04

15 0.141 0.84

25 0.048 0.28

35 0.059 0.35







(mm)





8B 5 0.275 1.64

15 0.081 0.48

25 0.065 0.39

35 0.067 0.40







(mm)





9A 5 0.142 0.84

15 0.094 0.56

25 0.055 0.33

35 0.048 0.28







(mm)





9B 5 0.215 1.28

15 0.133 0.79

25 0.071 0.42

35 0.049 0.29





Conclusions

Based on the test results, the following conclusions can be made:

1. All the cores, with the exception of cores 3A, 3B, 4A, 5A, 5B, 6A and 6B,exhibited normal chloride profiles – i.e., a decrease in the concentration of

chlorides with depth into concrete. The causes of the anomalies in chloride

profiles in the aforementioned cores could not be established.

2. Generally, the concentration of chloride ions within the test cores is high with

values ranging between 0.26 – 4.61% chlorides by mass of binder.

3. The susceptibility of the reinforcement that has been embedded in this

concrete to corrosion could not be determined owing to the fact that details

pertaining to the cover was not provided. Nevertheless, it can be concludedthat rebars at a cover depth less than 40 mm are highly susceptible to

corrosion owing to the fact that the measured chloride concentration are in

close proximity to the chloride threshold level of 0.4%.

Prof. Hans Beushausen Philemon Arito (PhD Student)

February 2013

yusuf's chloride analysis test results

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