FIGURE 3. ESEM photographs of the self-healing products on the crack surface of the sample and crack surface: (A) CS-28 sample; (B) CS-28 sample material magnified 2000 times; (C) AS-28 sample; (Bi) EDX spectrum of point A in (B); (Bii) EDX spectrum of point B in (B); (D) elemental maps (C,O, Ca, and Si) of the cracked surface of the CS-28 specimen.
Recently, our group introduced a test for generating crack permeability data for cementitious specimens . The test consisted of a novel method for creating defined crack widths in cementitious specimens and a simple and rapid permeability setup. Mortar cylinders were cast having two diametrically opposite grooves running down their sides. The specimens were split from groove to groove and spacers fitted to create defined parallel crack width geometries. The speed of the permeability setup meant that multiple replicates could be easily tested giving statistical power to the resultant crack permeability data. The ability of the test to create defined crack width geometries coupled with the easy testing of multiple replicates meant that reference permeabilities for cracked specimens could be generated against which autogenously healed cracked specimens could be quantified. Following this work, it was clear that a number of modifications could be made to improve the speed, accuracy, and reliability of the test. The current paper presents the modified test. To gauge for any improvement as a result of the modifications both the unmodified and modified tests were tested and compared.
CT and stereomicroscope images of cracked specimens. CT cross-sectional images of specimens with cracks intended to be a 200 µm, c 400 µm, and e 600 µm wide; and stereomicroscope images of specimens with cracks also intended to be b 200 µm, d 400 µm, and f 600 µm wide 2b1af7f3a8