Study on testing methods for water resistance of underwater cement paste

In this study, widely used methods like modified plunge, pH, suspend solid content and shaking tests are adopted to find the appropriated methods in expressing water resistance of Underwater cement paste (UWP). The visual inspection and parameter diagram are firstly analyzed and results show that, compared with the other two tests, the characters like water turbidity, non-dispersed particle and parametric graph change trend in modified plunge and pH tests are more consistence with practice situation. After that, the derivative analysis is studied correspondingly, from which the 0.6% PAM is found and proved to be the most suitable dosage on concerned paste composition and mass loss ratio no more than 1.0% and pH value less than 11.0 are determined as UWP anti-washout performance criterions subsequently. The standardized analysis is carried out later according to actual reflection, testing result, result accuracy and operation difficulty. The ultimate consequence in expressing UWP water resistance is confirmed as: pH test > modified plunge test > suspension solid content test > shaking test.