Chloride binding and time-dependent surface chloride content models for fly ash concrete
S. MUTHULINGAM1,B. N. RAO2,*()
1. Department of Civil Engineering, SSN College of Engineering, Kalavakkam 603 110, India 2. Structural Engineering Division, Department of Civil Engineering, Indian Institute of Technology Madras, Chennai 600 036, India
Corrosion of embedded rebars is a classical deterioration mechanism of reinforced concrete structures exposed to chloride environments. Such environments can be attributed to the presence of seawater, deicing or sea-salts, which have high concentrations of chloride ion. Chloride ingress into concrete, essential for inducing rebar corrosion, is a complex interaction between many physical and chemical processes. The current study proposes two chloride ingress parameter models for fly ash concrete, namely: 1) surface chloride content under tidal exposure condition; and 2) chloride binding. First, inconsistencies in surface chloride content and chloride binding models reported in literature, due to them not being in line with past research studies, are pointed out. Secondly, to avoid such inconsistencies, surface chloride content and chloride binding models for fly ash concrete are proposed based upon the experimental work done by other researchers. It is observed that, proposed models are simple, consistent and in line with past research studies reported in literature.
3.0431+ 0.6856 ln⁡(t) % wt. of cement
Song et al. [7]
[−0.379(w/b)+2.064]ln⁡(t) % wt. of binder
Chalee et al. [16]
0.26[ln⁡(3.77t+1)]+1.38 % wt. of binder
Pack et al. [27]
10[0.841(w/b)−0.213]+2.11t % wt. of binder
Petcherdchoo [17]
Tab.1
Fig.2
Fig.3
specimen
ψαL
ψβL
ψαF
ψβF
0% fly ash
34.27
2.83
8.20
0.32
25% fly ash
37.17
2.24
10.12
0.38
Tab.2
Fig.4
Binding isotherm constant
η1
η2
ψαL
34.2715
0.1161
ψβL
2.8349
− 0.0237
ψαF
8.2051
0.0767
ψβF
0.3237
0.0022
Tab.3
f/%
binding isotherm constant
ψαL (m3 of pore solution/m3 of concrete)
ψβL (m3 of pore solution/kg)
ψαF (m3 of pore solution/m3 of concrete)
ψβF
0
0.4621
0.0799
1.2354
0.3237
15
0.4855
0.0699
1.2486
0.3573
25
0.5012
0.0632
1.2483
0.3796
35
0.5169
0.0565
1.2408
0.4021
50
0.5404
0.0465
1.2158
0.4357
Tab.4
Fig.5
Fig.6
Fig.7
1
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