Factors influencing bugholes on concrete surface analyzed by image processing technology

• Published in: Construction & building materials 2017-10, Vol.153, p.897-907
• Main Authors: Liu, Baoju, Yang, Tengyu, Xie, Youjun
• Format: Article
• Language: English
• Subjects: Area ratio; Bugholes; Construction technology; Image processing; Mix proportions; Size distribution
• ISSN: 0950-0618; 1879-0526
• DOI: 10.1016/j.conbuildmat.2017.07.156

•The influence factors on the bugholes are quantitatively analyzed by image processing technology.•The area ratio, size distribution and maximum diameter of bugholes are evaluated.•The area ratio and the maximum diameter of bugholes have different influencing factors.•Appropriate mix proportions and vibration time is advantageous to reduce the bugholes. Bugholes are surface voids that result from the migration of entrapped air to the fresh concrete-formwork interface. The influencing factors, such as mix proportions and construction technology, on surface bugholes are quantitatively analyzed by image processing technology in this paper. The results show that the bughole area ratio of concrete and the maximum diameter of bugholes can be reduced by the methods of controlling the W/C ratio, superplasticizer content, sand ratio and fly ash content. Compared with saponifiable oil, the template paint can effectively reduce the maximum diameter and the area ratio of bugholes. Compared with wood formwork, the concrete surface using steel formwork and PVC formwork have higher amount of small bugholes and lower bughole area ratio, but the influence of formwork on the maximum diameter of bugholes on concrete surface is not significant. The concretes with different slump, mold release agents and formworks need different vibration time in order to decrease the bugholes on concrete surface, although long time vibration can reduce the surface bugholes, but the surface bugholes are difficult to be completely eliminated.