Apparent chloride diffusion coefficient (
), by bulk diffusion of UHPdC as per ASTM-C1556 (2004) was
carried out to determine the concentration of chloride agents of UHPdC
specimens. The tests were conducted on specimens that were immersed into the
exposed 4% concentration of chloride reagent for 120 days (refer to Figure 1)
with the results shown in Table 1. Preliminary result indicates the
value generally deceases with the increasing of the fiber
volume which shows the ease of chloride penetration into concrete will be
retarded within the fluid-filled pores, cracks and void spaces of concrete with
the increment of fiber quantities. Having say so, the actually retarding
mechanism of this chloride diffusion is yet to be understood and it is beyond
the scope of this research.
Table 1 shows the specimen without steel fiber (i.e. DU1) has the highest value of
= 0.136 x 10-6 mm2/s; whereas the UHPdC with 1% and 2% of steel fiber have an average values of 0.073 x 10-6 and 0.067 x 10-6, respectively. Of particular interest, the average value chloride diffusion coefficient value of is used for the standard UHPdC with 2% of steel fiber.
Chloride Diffusion Coefficient (ASTM-C1556,
2004)
Table 1 : Experimental results.
Figure 1 : Specimens immersed at salt water with
4% of chloride ions.