REDUCTION OF CHLORIDE ION INGRESS INTO REINFORCED CONCRETE USING A HYDROPHOBIC ADDITIVE MATERIAL

2017 ◽  
Vol 79 (2) ◽  
Author(s):  
Agus Maryoto ◽  
Buntara S. Gan ◽  
Han Aylie
Keyword(s):  
Compressive Strength ◽  
Reinforced Concrete ◽  
Chloride Ion ◽  
Chloride Ions ◽  
Calcium Stearate ◽  
Corrosion Attack ◽  
Reinforced Concrete Member ◽  
Load Carrying ◽  
Compressive Strength Test ◽  
Infiltration Test

Reinforced concrete structures located in areas near the coast are exposed to potential corrosion attack. Corrosion attack can occur because of the infiltration of chloride ions into concrete. At the initiation of the corrosion process, the load-carrying capacity of a reinforced concrete member will be affected negatively as a function of time. Infiltration of chloride ions into the concrete could be avoided by improving the micro-concrete properties. Enhancement of these properties can be achieved by use of an additive in the concrete. Calcium stearate is a hydrophobic material that can improve the properties of concrete. To determine the optimum contribution in concrete, laboratory experiments were conducted. Calcium stearate was added in varying contents of 0, 0.2, 0.9, and 1.9% of the cement weight. Four types of tests were performed to analyse the contribution of calcium stearate, namely the compressive strength test, absorption test, chloride ion infiltration test, and corrosion test. The results show that an optimum value of the compressive strength of concrete is obtained through the addition of calcium stearate. Besides that, the absorption, chloride ion infiltration, and corrosion value decrease significantly when a higher amount of calcium stearate is added to the concrete.  

scholarly journals The Compressive Strength and Resistivity toward Corrosion Attacks by Chloride Ion of Concrete Containing Type I Cement and Calcium Stearate

2018 ◽  
Vol 2018 ◽  
pp. 1-9
Author(s):  
Agus Maryoto ◽  
Buntara Sthenly Gan ◽  
Nor Intang Setyo Hermanto ◽  
Rachmad Setijadi
Keyword(s):  
Compressive Strength ◽  
Chloride Ion ◽  
Concrete Surface ◽  
Chloride Ions ◽  
Calcium Stearate ◽  
Type I ◽  
Compressive Strength Test ◽  
Strength Tests ◽  
Concrete Quality ◽  
Infiltration Test

This study aims to determine the effect of calcium stearate on concrete. Three kinds of concrete quality are studied, namely, 20, 30, and 40 MPa. Tests performed in the laboratory comprise a compressive strength test and an infiltration test of chloride ion content. The specimens used were cylinders with a diameter of 150 mm and height of 300 mm. The chloride ion infiltration test was carried out on a cube with sides of 150 mm. The infiltration of ions into the concrete was examined at depths of 1, 2, 4, 6, and 8 cm. Four dosages of calcium stearate were added to the concrete, namely, 0, 0.25, 1.27, and 2.53% for 20 MPa concrete; 0, 0.21, 1.07, and 2.48% for 30 MPa concrete; and 0, 0.19, 0.90, and 1.87% for 40 MPa concrete. The results of compressive strength tests indicate that the amount of calcium stearate that could be safely applied to the concrete was 0.25% of the weight of cement. On the other hand, the infiltration of chloride ions at a depth of 6 cm from the unprotected concrete surface decreased by 87, 69, and 113% for the 20, 30, and 40 MPa concrete, respectively, compared to concrete without calcium stearate. The test shows that the use of calcium stearate in concrete significantly increases its resistivity against corrosion attacks because, in the absence of chloride ions, the process of corrosion does not take place in the concrete.

Guidelines for flexural design of FRP reinforced concrete beams

2020 ◽  
pp. 002199832097373
Author(s):  
Fares Jnaid
Keyword(s):  
Compressive Strength ◽  
Reinforced Concrete ◽  
Carrying Capacity ◽  
Concrete Beams ◽  
Large Diameter ◽  
Reinforced Concrete Beams ◽  
Load Carrying Capacity ◽  
Concrete Compressive Strength ◽  
Load Carrying ◽  
Multiple Variables

This paper investigates the effects of different parameters on the live load carrying capacity of concrete beams reinforced with FRP bars. The author performed a parametric study utilizing an innovative numerical approach to inspect the effects of multiple variables such as reinforcement ratio, concrete compressive strength, span to depth ratio, FRP type, and bar diameter on load carrying capacity of FRP reinforced concrete beams. This study concluded that unless the span to height ratio is smaller than 8, tension-controlled sections are impractical as they do not meet code requirements for serviceability. In addition, it is recommended to use higher reinforcement ratios when using larger span to depth ratios and/or when using CFRP reinforcing bars. Moreover, larger number of bars with small diameter is more practical than fewer large diameter bars. Furthermore, this research suggests that increasing the concrete compressive strength is associated with a significant increase in the ultimate flexural capacity of FRP reinforced beams.

An Experimental Corrosion Investigation of Coupling Chloride Ions with Stray Current for Reinforced Concrete

2012 ◽  
Vol 166-169 ◽  
pp. 1987-1993 ◽  
Author(s):  
Mengcheng Chen ◽  
Kai Wang ◽  
Quanshui Wu ◽  
Zhen Qin
Keyword(s):  
Reinforced Concrete ◽  
Chloride Ion ◽  
Current Strength ◽  
Chloride Ions ◽  
Ion Concentration ◽  
Test Time ◽  
Light Rail ◽  
Stray Current ◽  
Concrete Deterioration ◽  
Two Stages

According to the service environment of light rail transit and subway structures, in this paper experiments on the corrosion characteristics of reinforced concrete under single corrosion environment of stray current, single corrosion environment of chloride ions and joint corrosion environment of stray current and chloride ions were respectively carried out. Loading direct current electric field was used to simulate the stray current. The experimental results showed that, the corrosion growth process of the rebar in reinforced concrete under single environment of chloride ions was slow and stable, while that under single environment of stray current being separated two stages, i.e., rapidly increasing stage and stably varying stage. In addition, the rebar of reinforced concrete in stray current alone environment was corroded faster than that in chloride ion alone environment did; when stray current and chloride ion coexist, the stray current speeded up the chloride ion transportation, which gave rise to the increase of the corrosion rate of the rebar of reinforced concrete; the corrosion degree of the rebar depended on the chloride ion concentration, stray current strength and test time. The stronger the stray current strength, the longer the stray current corrosion period and the heavier the chloride ion concentration, the more the corrosion products of the rebar and thus the more serious the reinforced concrete deterioration.

Mechanical Properties of Double Layer Rubberized Concrete Paving Blocks

2014 ◽  
Vol 911 ◽  
pp. 463-467 ◽  
Author(s):  
Euniza Jusli ◽  
Hasanan M. Nor ◽  
Putra Jaya Ramadhansyah ◽  
Haron Zaiton
Keyword(s):  
Compressive Strength ◽  
Double Layer ◽  
Fine Aggregate ◽  
Rubberized Concrete ◽  
Rubber Content ◽  
Waste Rubber ◽  
Load Carrying ◽  
Compressive Strength Test ◽  
Solid Load ◽  
Different Levels

This paper sought to evaluate the influences of different levels of waste rubber tyre (rubber granules) as an aggregate replacement in the production of double layer concrete paving blocks (CPBs). Waste rubber tyres were used as an aggregate replacement at the levels of 0%, 10%, 20%, 30%, and 40%. The characteristics of the double layer rubberized CPB were examined via a series of tests. According to the results, the density, porosity, and compressive strength of the double layer rubberized CPB is highly influenced by the percentage of rubber content. The compressive strength test has proven that by using rubber granules as an aggregate, the compressive strength is able to be manipulated. As the percentage of rubber granules increase, the compressive strength will decrease as the amount of solid, load-carrying material reduces. Compressive strength was at its peak when the rubber content was at 10%. 1-4 mm rubber granules were used as a replacement of fine aggregate and 5-8 mm rubber granules as coarse aggregate; both at the level of 40%. As a result, a double layer rubberized CPB with 28-days compressive strength of maximum 28 MPa is produced.

scholarly journals Durability Investigation of Carbon Fiber Reinforced Concrete under Salt-Freeze Coupling Effect

Materials ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 6856
Author(s):  
Yongcheng Ji ◽  
Wenchao Liu ◽  
Yanmin Jia ◽  
Wei Li
Keyword(s):  
Reinforced Concrete ◽  
Carbon Fiber ◽  
Coupling Effect ◽  
Chloride Ion ◽  
Chloride Ions ◽  
Fiber Reinforced Concrete ◽  
Ion Concentration ◽  
Fiber Reinforced ◽  
Ion Distribution ◽  
Carbon Fiber Reinforced

In order to study the durability behavior of CFRP (carbon fiber reinforced polymer) reinforced concrete, three category specimens (plain, partially reinforced, and fully reinforced) were selected to investigate its performance variation concerning chlorine salt and salt-freeze coupled environment, which included the microscopic examination, the distribution of chloride ion concentration, and the compressive properties. By observing the microscopic of the specimens, the surface and cross-section corrosion deterioration was examined with increasing exposure time, and the physical behavior of CFRP and core concrete were discussed. The chloride ion diffusion test exerted that the chloride ion concentration in plain specimens is at least 200 times higher than that of fully reinforced specimens. Therefore, the effectiveness of CFRP reinforcement will be proved to effectively hinder the penetration of chloride ions into the core section. The formula of the time-dependent effect of concrete diffusivity with salt-freeze coupling effect was presented and its accuracy verified. A time-varying finite element model of chloride ion distribution was established by using ABAQUS software. It can be seen from the axial compression test that the strength loss rate of three categories of specimens was varied when subjected to the corrosion environment. Therefore, it is proved that CFRP reinforcement can effectively reduce the deterioration of the specimen’s mechanical properties caused by the exposure environment. The research results can provide technical reference for applying the CFRP strengthened concrete in a severe salt-freeze environment.

scholarly journals A review on performance – based specification of durable concrete

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Elson John ◽  
Goldy Prince ◽  
Jessymol George
Keyword(s):  
Compressive Strength ◽  
Reinforced Concrete ◽  
Service Life ◽  
Low Cost ◽  
General Assumption ◽  
Chloride Ions ◽  
Actual Structure ◽  
Strength Performance ◽  
Rc Structures ◽  
Performance Specification

Concrete is the most common and widely used building material because of its relatively low cost, flexibility, and adaptability. Recent historical experience indicates that with exposed to aggressive chloride or carbonation-induced conditions, the reinforced concrete (RC) structures deteriorate prior to the expected service life. This is because of the general assumption that the concrete must be sufficiently durable if the strength requirements are adequate. The variability of concrete arising from the actual concreting procedures, such as placement, consolidation, finishing, and curing, does not take this assumption into account. In other words, the concrete cast for compressive strength in the specimens shows no similarity to the concrete in the actual structure. This paper provides a thorough analysis of the advancements that are taking place to achieve the long-term reliability of RC structures based on performance specifications. Keywords: reinforced concrete, service life, compressive strength, performance specification, durability, carbonation, chloride ions

scholarly journals Evaluation of Chloride Resistance of Early-Strength Concrete Using Blended Binder and Polycarboxylate-Based Chemical Admixture

2020 ◽  
Vol 10 (8) ◽  
pp. 2972 ◽  
Author(s):  
Taegyu Lee ◽  
Jaehyun Lee
Keyword(s):  
Compressive Strength ◽  
Diffusion Coefficient ◽  
Portland Cement ◽  
Chloride Ion ◽  
Strength Criterion ◽  
Chloride Ions ◽  
Chloride Diffusion ◽  
Chloride Diffusion Coefficient ◽  
Characteristic Strength ◽  
Early Strength

The mixing proportions of concrete were examined with regard to the durability performance and early strength in coastal areas. Research was conducted to improve the C24 mix (characteristic strength of 24 MPa). C35 concrete (characteristic strength of 35 MPa) was selected as a comparison group, as it exhibits the minimum proposed strength criterion for concrete in the marine environment. To secure the early strength of the C24 concrete, 50% of the total ordinary Portland cement (OPC) binder was replaced with early Portland cement (EPC); and to provide durability, 20% was substituted with ground granulated blast-furnace slag (GGBS). In addition, a polycarboxylate (PC)-based superplasticizer was used to reduce the unit water content. The compressive strength, chloride ion diffusion coefficient, chloride penetration depth, and pore structure were evaluated. After one day, the compressive strength improved by 40% when using EPC and GGBS, and an average increase of 20% was observed over 91 days. EPC and GGBS also reduced the overall porosity, which may increase the watertightness of concrete. The salt resistance performance was improved because the rapid early development of strength increased the watertightness of the surface and immobilization of chloride ions, decreasing the chloride diffusion coefficient by 50%.

Exposure Test of FRP-Reinforced Concrete Structure in Temperate Marine Tide Zone

2012 ◽  
Vol 166-169 ◽  
pp. 538-542
Author(s):  
Ming Jin Chu ◽  
Zhi Juan Sun ◽  
Hui Chen Cui ◽  
Ke Zhang
Keyword(s):  
Reinforced Concrete ◽  
Concrete Structure ◽  
Chloride Ion ◽  
Test Results ◽  
Reinforced Concrete Structure ◽  
Freezing And Thawing ◽  
Concrete Member ◽  
Exposure Test ◽  
Reinforced Concrete Member ◽  
Marine Zone

Through exposure test of FRP-reinforced concrete member in littoral test area of temperate marine zone, the durability and constructional measures of FRP-reinforced concrete structure are investigated. The test results show that FRP shell on the surface of FRP-reinforced concrete member is effective in avoiding wave flush, freezing and thawing damage, preventing chloride ion corrosion and improving durability. On the other hand, reliable measures should be taken to protect concrete structures with no FRP shell on the surface. Based on above, the provided reference for evaluation durability of FRP-reinforced concrete structure, and proper constructional measures for FRP-reinforced concrete structure are presented.

scholarly journals Strengthening of R.C Short Column with Partial Replacement of Bacillus Bacteriain Cement

2019 ◽  
pp. 362-372
Author(s):  
VijayaSundravel K ◽  
Ramesh S ◽  
Jegatheeswaran D
Keyword(s):  
Compressive Strength ◽  
Carrying Capacity ◽  
Ultimate Load ◽  
Strength Test ◽  
Partial Replacement ◽  
Load Carrying Capacity ◽  
Load Carrying ◽  
Compressive Strength Test ◽  
Axial Compressive Strength ◽  
Ultimate Load Carrying Capacity

In this paper the strength behavior of Bacillus Bacteria and strengthening characteristic of GFRP sheets are investigated. In this study the optimum percentage of Bacillus Bacteria is find out from the compressive strength test. The cubes are casted based on the percentage replacement of Bacillus Bacteria in cement. The replacement of Bacillus Bacteria in cement is 0%, 10%, 20%, 30% 40%, 50%. Totally 18 cubes are casted out of this 3 cubes for each percentage. After 28 days the compressive strength was find out from the cubes. From the compressive strength test the optimum percentage of Bacillus Bacteria is concluded as 20%. Based on these result columns are casted. Totally 12 columns are casted out of these columns 6 columns are conventional and 6 columns are Bacillus Bacteria replace columns. The axial compressive strength test was carried on 3 conventional and 3 Bacillus Bacteria replaced column to find out the ultimate load carrying capacity. From this ultimate load 70% of load is given to the remaining columns as a preloading. After given the preloading these columns are strengthened by using GFRP sheets. The strengthened columns are tested under axial compression test. From this result the ultimate load carrying capacity, deflection, stiffness, and energy absorption of column is calculated.

scholarly journals An analysis of fresh, mechanical and durability properties of lightweight self-consolidating fiber reinforced concrete

2021 ◽  
Author(s):  
Imge Nicole Celasun
Keyword(s):  
Compressive Strength ◽  
Reinforced Concrete ◽  
Flexural Strength ◽  
Chloride Ion ◽  
Crumb Rubber ◽  
Fiber Content ◽  
Fiber Reinforced Concrete ◽  
Fiber Reinforced ◽  
Acid Attack ◽  
Chloride Permeability

This research investigated the fresh, mechanical and durability behavior of lightweight self-consolidating fiber reinforced concrete (LWSCFRC) with four different fibers (Polyethylene, Polyvinyl Alcohol, High-Density Polyethylene and Crumb Rubber). Two LWSCFRC mixtures were created for each fiber to analyze the effects of increasing fiber content on fresh state properties: slump flow and density. Mechanical and durability tests included compressive/ flexural strength, rapid chloride permeability and resistance to acid attack. The increase in fiber content decreased the workability of LWSCFRC mixtures except for crumb rubber. Flexural strength of all LWSCFRC specimens was similar compared to their control counterparts, while crumb rubber exhibited the highest compressive strength from all fiber specimens. Addition of fibers resulted in good resistance against chloride ion penetration but compressive strength of specimens in a 5% sulfuric acid solution decreased. Overall, 1.0% Crumb Rubber performed better in fresh, mechanical and durability testing from all the fiber specimens.

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