scholarly journals REDUCING CONCRETE PERMEABILITY BY USING NATURAL POZZOLANS AND REDUCED AGGREGATE-TO-PASTERATIO

2015 ◽  
Vol 21 (2) ◽  
pp. 165-176 ◽  
Author(s):  
Fernando Bustos ◽  
Patricia Martinez ◽  
Carlos Videla ◽  
Mauricio Lopez
Keyword(s):  
Cement Content ◽  
Blended Cement ◽  
Chloride Ion ◽  
Air Permeability ◽  
Ion Diffusion ◽  
Natural Pozzolans ◽  
Concrete Permeability ◽  
Cementing Material ◽  
Chloride Ion Diffusion ◽  
Durability Of Concrete

Improved durability of concrete is mainly achieved with low-permeability. Permeability depends on permeability of the bulk cement paste (CP) and that of its interfacial transition zone (ITZ). Even though permeability of CP is well understood and can be adequately controlled, permeability of ITZ is not well understood yet. This paper shows that minimizing permeability of concrete requires minimizing permeability of CP by using a supplementary cementing material (SCM) such as natural pozzolans (NP) and minimizing ITZ by reducing aggregate content until maximum cement content. This was done by comparing performance of concrete made with ordinary Portland cement (OPC) and blended cement (OPC+NP) at the same w/b, and by comparing performance of concrete with different amount of ITZ at the same w/b. All of this was performed through testing of mechanical properties, air permeability, sorptivity, chloride ion diffusion, and aggregate specific surface. Results show that NP reduced air permeability by 84% and chloride ion diffusion by 66%, but increased sorptivity up to 140%. ITZ has an important effect in all properties; especially in air permeability where sensitive reduction of more than a 90% was achieved. ITZ effect seems to be as important as using SCMs in improving durability of concrete.

scholarly journals Evaluation of Relationship between Water Absorption and Durability of Concrete Materials

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
S. P. Zhang ◽  
L. Zong
Keyword(s):  
Compressive Strength ◽  
Surface Water ◽  
Water Absorption ◽  
Chloride Ion ◽  
Sulfate Attack ◽  
Ion Diffusion ◽  
Curing Conditions ◽  
Concrete Materials ◽  
Chloride Ion Diffusion ◽  
Durability Of Concrete

Environment has significant effects on the water absorption of concrete materials. This paper presents an experimental study of the influence of water absorption on the durability of concrete materials. A detailed analysis is also presented in order to establish useful relationship between them. Concrete specimens of different water absorption were prepared through different curing conditions, and results indicated that curing condition can significantly affect the surface water absorption. SEM photos also showed that different curing conditions caused different microstructure. After 28-days curing, compressive strength, permeability, sulfate attack, and chloride ion diffusion of concrete samples were investigated. As a result, both of surface sorptivity and internal sorptivity have no clear relationship with compressive strength. Results obtained also showed that only surface water absorption related to the performance of concrete including permeability, sulfate attack, and chloride ion diffusion. In addition, both impermeability and resistance to sulfate attack were linearly associated with surface sorptivity, and both correlation coefficients were not less than 0.9. Furthermore, chloride ion diffusion coefficient has exponent relation to surface water absorption with higher correlation coefficient. However, no apparent relationship was found between internal water absorption and durability like impermeability, resistance to sulfate attack, and chloride ion diffusion.

The Mix Design of Low Strength High Flowing Concrete with Low Cement Content Prepared by Manufactured Sand

2011 ◽  
Vol 413 ◽  
pp. 201-206
Author(s):  
Zhan Ao Liu ◽  
Ming Kai Zhou ◽  
Xiao Chen
Keyword(s):  
Cement Content ◽  
Design Method ◽  
Chloride Ion ◽  
Mix Design ◽  
Ion Diffusion ◽  
Natural Sand ◽  
Manufactured Sand ◽  
Low Strength ◽  
Chloride Ion Diffusion ◽  
By Products

Aiming at the engineering status of the shortage of natural sand and the contradictory between workability and strength surplus emerging in the design of low strength high flowing concrete (LHC), this paper has proposed a mix design method of LHC with low cement content prepared by manufactured sand (MS).And then verifies the feasibility of the method through experiments. Tests on slump, compressive strength and chloride ion diffusion coefficient were carried out and the results indicate that LHC with low cement content prepared by MS can be successfully produced using this method. Concrete designed by this method has low cement consumption and has utilized MS to replace NS as well as made full use of the industrial by-products of stone fines and fly ash. As a result, it is economical and ecological.

Relation of Permeability by High Hydraulic Method and Chloride Ion Diffusion Coefficient of Concrete

2009 ◽  
Vol 405-406 ◽  
pp. 303-308
Author(s):  
Yong Ge ◽  
Jie Fan ◽  
Jie Yuan ◽  
Wen Cui Yang ◽  
Bao Sheng Zhang ◽  
...  
Keyword(s):  
Diffusion Coefficient ◽  
Chloride Ion ◽  
Ion Diffusion ◽  
Quick Method ◽  
Air Content ◽  
Testing Period ◽  
Hydraulic Method ◽  
Concrete Permeability ◽  
Relationship Of ◽  
Chloride Ion Diffusion

Permeation length, permeation coefficient of water permeated into concrete and chloride ion diffusion coefficient of C30, C45 and C60 concrete were studied by high hydraulic method (0.5MPa~25MPa) and quick method of testing chloride ion diffusion respectively, and relationship of concrete permeability tested by two methods was analyzed too. High hydraulic method can distinguish permeability of concrete with different strength or air content and it is a quick and effective method to fast test and evaluating permeability of concrete. The results showed that high hydraulic method is applicable for evaluating permeability of concrete, with advantages of short testing period, easy operating and simple pretreatment of concrete specimens. Permeation coefficient or permeation length of water permeated into concrete exhibited linear relationship with chloride ion diffusion coefficient of concrete. It is applicable for evaluating permeability of concrete using quick method of testing chloride ion diffusion.

Modeling of Chloride Ion Diffusion in Concrete under Fatigue Loading

2018 ◽  
Vol 23 (1) ◽  
pp. 287-294 ◽  
Author(s):  
Tao Yang ◽  
Bowen Guan ◽  
Guoqiang Liu ◽  
Yanshun Jia
Keyword(s):  
Chloride Ion ◽  
Fatigue Loading ◽  
Ion Diffusion ◽  
Chloride Ion Diffusion

EFFECT OF CRUMB RUBBER ON CONCRETE STRENGTH AND CHLORIDE ION PENETRATION RESISTANCE

2015 ◽  
Vol 77 (32) ◽  
Author(s):  
Nurazuwa Md Noor ◽  
H. Hamada ◽  
Y. Sagawa ◽  
D. Yamamoto
Keyword(s):  
Structural Strength ◽  
Salt Water ◽  
Chloride Ion ◽  
Crumb Rubber ◽  
Rubberized Concrete ◽  
Migration Test ◽  
Ion Diffusion ◽  
Steady State Condition ◽  
Chloride Ion Penetration ◽  
Chloride Ion Diffusion

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.

Models for Chloride Ion Diffusion in Archaeological Iron

2001 ◽  
Vol 46 (2) ◽  
pp. 109-120
Author(s):  
L.S. Selwyn ◽  
W.R. Mckinnon ◽  
V. Argyropoulos
Keyword(s):  
Chloride Ion ◽  
Ion Diffusion ◽  
Archaeological Iron ◽  
Chloride Ion Diffusion

Durability of Self-Compacting Concrete

2011 ◽  
Vol 324 ◽  
pp. 340-343
Author(s):  
Abdelaziz Benmarce ◽  
Hocine Boudjehem ◽  
Robila Bendjhaiche
Keyword(s):  
Oxygen Permeability ◽  
Chloride Ion ◽  
Chemical Characteristics ◽  
Capillary Absorption ◽  
Ion Diffusion ◽  
Self Compacting Concrete ◽  
Fresh State ◽  
Physical And Chemical ◽  
Transfer Properties ◽  
Chloride Ion Diffusion

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).

Sign in / Sign up

Export Citation Format

Share Document