Durability of concrete covering layer of reinforced concrete slabsfor earth dam slope protection

Abstract

In Lithuania there are over 1000 ponds constructed and 620 have been evaluated as potentially dangerous hydraulic structures. Our water-retaining infrastructure deteriorates under environmental impacts, therefore the ageing of building materials causes a greater probability of deterioration and even failure. Durability of hydraulic structures depends on maintenance circumstances, surveillance, timely repair of structures or rehabilitations. Prognosis of the deterioration speed and durability of slabs is the main problem in each pond. The durability of concrete slabs covering layer can be evaluated by time (Tlayer), which equals the time to expose reinforcement of a reinforced concrete structure. Based on the results of the field investigation, the modelling of durability of reinforced concrete slabs for earth dam slope protection was performed. Regularities of concrete compression strength of reinforced concrete slabs for earth dam slope protection under the influence of freezing–thawing cycles and other environmental factors were established. Using the developed durability evaluation method of reinforced concrete slabs for earth dam slope protection, the remaining service life of theconstruction till the probable beginning (T5 %) or end of its deterioration (T50 %) may be calculated. It is also possible to determine the time (Tlayer), during which the reinforcement of the reinforced concrete construction is uncovered/exposed. Using the estimated constant of degradation in designing of reinforced concrete slabs for earth dam slope protection for using them at changing water level, there is a possibility to choose concrete of such strength, that the reinforcement of the construction would not be exposed during the intended period of usage.