5Example
To illustrate the use of 4SIGHT, consider the following fictitious example. The concrete was designed with a 0.40 water:cement ratio (WC=0.40). Experimental diffusivity measurements using Cl– ions gave 5.0 × 10-12 m2/sec (DIFF=5.0E-12). No permeability measurements are available. The roof slab is 1.0 meter thick (THICKNESS=1.000). Regularly spaced cracks have been observed on the bottom of the slab. The cracks are approximately 100 μm wide, spaced 2 meters apart, and are assumed to extend upwards to the neutral axis which is 25 centimeters from the bottom of the roof slab (CRACK = 0.000100 AT 2.0 DEPTH 0.25). Also, the roof is buried, giving an effective pressure head of 2 meters. (HEAD = 2.0).
Soil analysis indicates the presence of SO2–4 at a concentration of 1.0 moles per liter (EXTERNAL SO4 = 1.0). Engineering analysis indicates that if the sulfate degradation penetrates down 20 centimeters from the top surface of the roof then the vault will collapse (DEPTH = 0.20). Additionally, chloride ions are present in the soil at a concentration of 0.40 moles per liter (EXTERNAL Cl = 0.40). and engineering drawings indicate that the reinforcement bars are located 60 centimeters from the top of the roof (REBAR = 0.60). Thorough soil analysis indicates that sodium ions are also present at a concentration of 2.40 moles per liter (EXTERNAL Na = 2.40), giving a nearly neutral soil pH.
Internal to the concrete the pH is approximately 13. Therefore, internal potassium and sodium concentrations are approximately 0.1 (INTERNAL K = 0.1) and 0.05 (INTERNAL Na = 0.05) moles per liter, respectively.
To monitor the ingress of the external ions, calcium (OUTPUT Ca) and chloride (OUTPUT Cl) ions will be included in the output of the final state of the system. Also, to monitor leaching, the solid calcium hydroxide content will also be included in the output (OUTPUT Ca OH).
The input file for this example, example.dat is included in the distribution diskette and reiterated here:
| DIFF = 5.0E-12 WC = .40 THICKNESS = 1.000 EXTERNAL Na = 2.40 EXTERNAL Cl = 0.400 EXTERNAL SO4 = 1.00 INTERNAL K = 0.1000 INTERNAL Na = 0.500 OUTPUT Ca OUTPUT Cl OUTPUT Ca OH REBAR = .8000 |
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