An Orthogonal Test Study on the Preparation of Self-Compacting Underwater Non-Dispersible Concrete.

To ensure a limited washout loss rate and the self-compaction of underwater concrete, the mix proportion design of underwater non-dispersible concrete is a key technology that has not been completely mastered. In view of this aspect, an orthogonal test study was carried out in this paper on the workability, washout resistance, and compressive strength of underwater non-dispersible concrete. Six factors with five levels were considered, which included the water/binder ratio, the sand ratio, the maximum particle size of the coarse aggregate, the content of the dispersion resistance agent, the content of superplasticizer, and the dosage of fly ash. Using a range and variance analysis, the sensitivity and significance of these factors were analyzed on the slump and slump-flow, the flow time, the washout loss rate, the pH value, and the compressive strength at the curing ages of 7 days and 28 days. The results indicated that the water/binder ratio and the content of the dispersion resistance agent were strong in terms of their sensitivity and significance on the workability and washout resistance, and the water/binder ratio and the dosage of fly ash were strong in terms of their sensitivity and significance on the compressive strength. With the joint fitness of the test results, formulas for predicting the slump-flow, washout loss rate, and compressive strength of underwater non-dispersible concrete were proposed considering the main impact factors.