Proceedings of The 5th International Conference on Modern Research in Engineering, Technology and Science
Influence of Dried Concrete Sludge on the Properties of Hardened Cement Paste
Edvinas Pocius,and Džigita Nagrockienė
This paper presents the research into the effect of dried concrete sludge on the properties of fresh and hardened cement paste. Concrete washout slurry was also investigated which accumulates in concrete plants. Concrete washout slurry is being created from regenerated water, which have too big density to use it in fresh concrete mixes. Cement paste mixtures were made from cement, superplasticiser, water and dried concrete sludge. Cement in the mixture was replaced by concrete sludge at 0 % – 30 %. The chemical, mineral compositions and particle size distribution of the dried concrete sludge was determined. The slump of the cement paste with different content of dried concrete sludge was measured. The density, the compressive and flexural strengths of hardened cement paste containing different amounts of dried concrete sludge were tested. The tests revealed that both technological and mechanical properties of the specimens deteriorated with the increase of dried sludge content. The test results suggest that the replacement of cement by dried concrete sludge has a negative effect on mechanical properties of hardened cement paste. A slight strength decrease observed in specimens where 5 % of cement was replaced with dried concrete sludge suggests that the replacement of cement at 5 % is appropriate and could be passible.
keywords: concrete waste, concrete sludge, hardened cement paste.