scholarly journals FUNDAMENTAL STUDY ON CHLORIDE ION DIFFUSION AND STEEL CORROSION IN SILICA FUME CONCRETE

2011 ◽  
Vol 65 (1) ◽  
pp. 360-367
Author(s):  
Shinichi KAWAHARA ◽  
Tatsuhiko SAEKI ◽  
Tsuyoshi SHIMA ◽  
Hironori YOSHIZAWA
Author(s):  
Silas de Andrade Pinto ◽  
Sandro Lemos Machado ◽  
Daniel Véras Ribeiro

Abstract Corrosion is one of the main phenomena that lead to pathological manifestations in reinforced concrete structures under aggressive environments. with the chloride ion being the most responsible for its occurrence. In this way, understanding the transport mechanisms of this ion through the microstructure of the concrete is of fundamental importance to prevent or delay the penetration of these aggressive agents to guarantee a durable structure. In the literature, there are extensive studies concerning the diffusion of chlorides in concrete and the influence of pozzolanic additions in this mechanism. However, only a few correlate the different methods of analysis. This work aims to determine the chloride ion diffusion coefficients in concrete containing various levels of silica fume (5%, 10%, and 15%) or varying the mortar content (54%, 80%, and 100%), and compares the results obtained through column tests and chloride migration tests. It was observed that, although the techniques used were quite distinct, the diffusion values obtained were similar, contributing to the validation of both techniques. Furthermore, the variation in the mortar ratio causes a reduction in the interfacial transition zone of coarse aggregate/mortars and an increase in the content of aluminates, which promotes a similar effect to the use of silica fume.


2018 ◽  
Vol 23 (1) ◽  
pp. 287-294 ◽  
Author(s):  
Tao Yang ◽  
Bowen Guan ◽  
Guoqiang Liu ◽  
Yanshun Jia

2015 ◽  
Vol 77 (32) ◽  
Author(s):  
Nurazuwa Md Noor ◽  
H. Hamada ◽  
Y. Sagawa ◽  
D. Yamamoto

This paper present the effect of crumb rubber on its ability to produce concrete with structural strength when it was used directly from the plant without any treatment process. Crumb rubber was added as fine aggregates at 0%, 10%, 15% and 20% of sand volume meanwhile silica fume was added at 10% by cement weight. Three main series of concrete namely rubberized concrete with water-to-cement ratio of 50% and 35% was design and development of compressive strength was observed from day 7 until 91 days. Also, effectiveness of crumb rubber under flexural strength and splitting tensile strength was studied at 28 days curing age. Effect of crumb rubber on durability performance was done on chloride ion penetration resistance performance by migration test and by immersion in salt water. Chloride ion diffusion in rubberized concrete by migration test was carried out under steady state condition using effective diffusion coefficient, De meanwhile, immersion test in salt water was conducted under non-steady state condition using apparent diffusion coefficient, Da. Results showed that compressive strength was decrease with the increasing of crumb rubber in the mixture.  Even though the strength were reducing with the inclusion of crumb rubber, the reduction were less than 50% and it achieved acceptable structural strength. Chloride transport characteristics were improved by increasing amount of CR and rubberized concrete with w/c = 0.35 gave better resistance against chloride ion compared to w/c = 0.50 with more than 50% difference. Silica fume provide slightly strength increment compared to normal rubberized concrete and the same behavior was observed during chloride ion diffusion test.


2001 ◽  
Vol 46 (2) ◽  
pp. 109-120
Author(s):  
L.S. Selwyn ◽  
W.R. Mckinnon ◽  
V. Argyropoulos

2011 ◽  
Vol 324 ◽  
pp. 340-343
Author(s):  
Abdelaziz Benmarce ◽  
Hocine Boudjehem ◽  
Robila Bendjhaiche

Abstract. Self compacting concrete (SCC) seem to be a very promising materials for construction thanks to their properties in a fresh state. Studying of the influence of the parameters of specific designed mixes to their mechanical, physical and chemical characteristics in a state hardened is an important stage so that it can be useful for new-to-the-field researchers and designers (worldwide) beginning studies and work involving self compacting concrete. The objective of this research is to study the durability of self compacting concrete. The durability of concrete depends very much on the porosity; the latter determines the intensity of interactions with aggressive agents. The pores inside of concrete facilitate the process of damage, which began generally on the surface. We are interested to measure the porosity of concrete on five SCC with different compositions (w/c, additives) and vibrated concrete to highlight the influence of the latter on the porosity, thereafter on the compressive strength and the transfer properties (oxygen permeability, chloride ion diffusion, capillary absorption).


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