PMC

Examples of criteria of pixel-based labeling for construction site images (original: left; labeled: right; red: nonconcrete; blue: concrete): (a) Every concrete area was labeled, even the shadows and the dark spots. (b) The whole image was labeled as ‘not concrete’ since there were no traces of concrete. (c) The reinforcement bars were avoided as much as possible. (d) The people were omitted. Moreover, the fresh concrete below reinforcements was also omitted. (e) Only the fresh and young concrete was labeled as concrete. Old concrete and concrete covered by paint was omitted. (f) When the concrete was covered with a transparent sheet, the areas where the sheet was in contact with concrete were labeled as ‘concrete’. (g) Wet regions or concrete covered with water was also labeled as ‘concrete’. (h) When the area covered with concrete was in an extreme darkness, it was labeled as ‘nonconcrete’.

SEM images of OC and F10S20 concrete: (a) Microstructure of OC concrete at 3 d; (b) Microstructure of F10S20 concrete at 3 d; (c) Microstructure of OC concrete at 28 d; (d) Microstructure of F10S20 concrete at 28 d; (e) ITZ of OC concrete at 28 d; (f) Magnified ITZ of OC concrete at 28 d; (g) ITZ of F10S20 concrete at 28 d; (h) Magnified ITZ of F10S20 concrete at 28 d.

Test specimen after rebar corrosion: (a) Reference concrete, W/C = 0.55; (b) 50 kg/m³ rubber aggregate concrete, W/C = 0.55; (c) 100 kg/m³ rubber aggregate concrete, W/C = 0.55; (d) 150 kg/m³ rubber aggregate concrete, W/C = 0.55; (e) Reference concrete, W/C = 0.45; (f) 50 kg/m³ rubber aggregate concrete, W/C = 0.45; (g) 100 kg/m³ rubber aggregate concrete, W/C = 0.45 and (h) 150 kg/m³ rubber aggregate concrete, W/C = 0.45.

Permeability of (a) concrete with 25% crushed RCA, (b) concrete with 50% crushed RCA, (c) concrete with 75% crushed RCA, (d) concrete with 25% round RCA, (e) concrete with 50% round RCA, (f) concrete with 75% round RCA.