Deformation-deterioration phenomenon of marine concrete by chloride penetration and the effect of silica fume

摘要

Studies on concrete and reinforced concrete with silica fume (produced from rawmaterials such as coke, coal, wood chips and quartz) in tidal zone influenced by hot-dryWestern wind from Lao’s) are carried out step by step. In this paper three examination stepshave presented.The first step is to research the deformation - deterioration phenomenon by comparing inthe case of with load samples (making tension zone and compression zone, i.e. pulling stressesand pressing stresses) and samples without load in two areas such as Hanoi and Cua Loseaport.Hanoi is about 100km far from sea, and Cua Lo seaport is near Vinh city – Nghe Anprovince at the zone located in the North Middle region of Vietnam where the samples areinfluenced by the hot-dry Western wind from Lao’s to research Vietnam. The site for testingsamples is in tidal zone. The results of the first step are correlated with the effects of climateand pulling stresses under the influences of chloride from sea water in tidal zone affecting inthe working process of reinforced concrete samples without silica fume which are measured byultrasonic equipment.The second step is to examine chloride penetration by determining the concentration ofchloride at each depth of concrete samples soaked in tidal zone for 4 years and to determine theamount of chloride in the normal concrete samples and the concrete samples with silica fumeand super-plasticizer. The results of the second step show the chloride concentration in theconcrete sample with silica fume and super-plasticizer less than in the normal concrete at thesame depth from the face of concrete samples.The third step is to determine the lifetime of the reinforced concrete with silica fume andsuper-plasticizer in a tidal zone, this being an important factor. Based on chloride concentrationat the depth of face of the steel bar in concrete, the authors have calculated the first stagelifetime (trace of corrosion on the face of steel bar is observed). The results of the third step areas follows: the first stage lifetime of the reinforced concrete with silica fume and super plasticizer is 23 years; the first stage lifetime of the reinforced concrete with only superplasticizerwithout silica fume is 17.2 years.The second step and the third step show the role of silica fume for the marine concreteinfluenced by hot-dry Western wind from Lao’s to Vietnam.