Study on Qingdao Bay Bridge Pier Concrete Anti Cl- Permeability Change Law and Structural Durability Analysis

2013 ◽  
Vol 405-408 ◽  
pp. 2649-2652
Author(s):  
Zhi De Huang
Keyword(s):  
Diffusion Coefficient ◽  
Chloride Ion ◽  
Concrete Specimen ◽  
Cementitious Materials ◽  
Permeability Change ◽  
Ion Permeability ◽  
Resistance Change ◽  
Hydration Mechanism ◽  
Durability Analysis ◽  
Structural Durability

Entity structure concrete chloride ion permeability resistance change law were studied, relying on Qingdao Bay Bridge project, using entity structure concrete specimen under the same condition maintenance, using RCM method test diffusion coefficient at the age of 28d,60d,90d,1y and 2y. Different mixture concrete chloride ion permeability resistance change law were Interoperated in essence, combining with cementitious materials hydration mechanism.

scholarly journals Effect of nano-silica as cementitious materials-reducing admixtures on the workability, mechanical properties and durability of concrete

2021 ◽  
Vol 10 (1) ◽  
pp. 1395-1409
Author(s):  
Changjiang Liu ◽  
Xin Su ◽  
Yuyou Wu ◽  
Zhoulian Zheng ◽  
Bo Yang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Building Materials ◽  
Setting Time ◽  
Microscopic Analysis ◽  
Chloride Ion ◽  
Cementitious Materials ◽  
Hydration Reaction ◽  
Ion Permeability ◽  
Nano Silica ◽  
Durability Of Concrete

Abstract Nano-silica (NS) is one of the most important nanomaterials in recent years. It is used as a new cement-based composite reinforcement in building materials because of its high volcanic ash activity. In order to achieve the goal of carbon peaking and carbon neutralization, combined with the research idea of cementitious materials-reducing admixture for concrete, under the condition of reducing the amount of cement in concrete by 20%, the influence of different dosages of NS on the setting time and mechanical properties of concrete was analyzed. In addition, the shrinkage performance, impermeability, and resistance to chloride-ion permeability of concrete were also studied. The results show that under the same curing conditions and ages, when the NS dosage is 2.5%, the compressive strength and splitting tensile strength of the specimen after 28 days of curing are the highest, reaching 40.87 and 3.8 MPa, which show an increase by 6.6 and 15.15%. The shrinkage performance of concrete increases with the increase in NS dosage. In addition, when the NS dosage is 2.0%, the durability of concrete has also been greatly improved. The impermeability of concrete increased by 18.7% and the resistance to chloride-ion permeability increased by 14.7%. Through microscopic analysis it was found that NS can promote the hydration reaction, generate more hydration products such as calcium silicate hydrate (C–S–H), enhance the interfacial adhesion between the matrix and the aggregate, and form a closer interfacial transition zone. Moreover, the addition of NS also reduces the cumulative pore volume in concrete, refines the pore size, and makes the internal structure of concrete denser.

Theoretical Analysis of Chloride Ion Migration Tests in Cementitious Material Research

2012 ◽  
Vol 450-451 ◽  
pp. 21-25
Author(s):  
Jin Bo Yang ◽  
Reng Guang Liu
Keyword(s):  
Diffusion Coefficient ◽  
Theoretical Calculations ◽  
Chloride Ion ◽  
Cementitious Materials ◽  
Chloride Diffusion ◽  
Chloride Diffusion Coefficient ◽  
Accelerated Tests ◽  
Penetration Test ◽  
Migration Test ◽  
Ion Migration

Chloride ion migration tests, or so called electrical accelerated tests, for testing chloride diffusion coefficient of cementitious materials are reviewed. The ion migration theory of electrical accelerated tests is presented. Four main representative measures, chloride penetration test, steady state migration test, unsteady state migration test and salt saturated conductivity test, are introduced and their theoretical calculations of chloride diffusion coefficient are described. Through analysis of the theoretical calculations, it could be found that all electrical accelerated tests are based on ion migration theory although different suppositions are adopted. Steady state migration test is the most suitable measure to determine chloride diffusion coefficient among the migration tests. DCIPT, DRCM and DSSCT calculated by chloride penetration test, unsteady state migration test and salt saturated conductivity test could be used to identify the resistance to chloride ion penetration of cementitious materials but are not the real diffusion coefficient.

scholarly journals Properties and Hydration Mechanism of Soda Residue-Activated Ground Granulated Blast Furnace Slag Cementitious Materials

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2883
Author(s):  
Yonghui Lin ◽  
Dongqiang Xu ◽  
Xianhui Zhao
Keyword(s):  
Blast Furnace ◽  
Blast Furnace Slag ◽  
Binding Capacity ◽  
Chloride Ion ◽  
Cementitious Materials ◽  
Industrial Solid Waste ◽  
Hydration Mechanism ◽  
Granulated Blast Furnace Slag ◽  
Free Chloride ◽  
Furnace Slag

Soda residue (SR), an industrial solid waste, pollutes the environment due to its high alkalinity and chloride ion content. SR can be used as an alkali activator of ground granulated blast furnace slag (GGBFS). This study investigated the effects of four types of SR-activated GGBFS cementitious materials (pastes) with different mass ratios of SR to GGBFS (8:92, 16:84, 24:76, 34:68) on the physical properties, mechanical strength, and chloride binding capacity. The hydration mechanism of the pastes was also studied. Results showed that with the increasing addition of SR, the density of the pastes decreased, and more white aggregates of SR appeared causing the increase of water absorption and porosity of the pastes. The pastes with 16% SR addition had the maximum compressive strength (34.1 MPa, 28 d), so the optimum proportion of SR addition in the pastes was 16%. With the increases of SR addition, the amount of chloride element in the initial pastes increases. When the proportion of SR addition is 8%, the mass percentage of free chloride ion in the pastes at 28 d is 0.13%. The main hydration products of the pastes were C–S–H gels, ettringite, and Friedel’s salt, and the amount of ettringite varied with the amount of SR addition and curing time.

Compressive Strength and Chloride Ion Permeability Test of Concrete Incorporating Fly Ash and GGBS with Diverse Water Binder Ratio

2022 ◽  
Vol 1048 ◽  
pp. 311-320
Author(s):  
Tarun Gehlot ◽  
Suresh Singh Sankhla ◽  
Sangeeta Parihar
Keyword(s):  
Fly Ash ◽  
Compression Test ◽  
Chloride Ion ◽  
Cementitious Materials ◽  
Mineral Admixture ◽  
Supplementary Cementitious Materials ◽  
Permeability Test ◽  
Ion Permeability ◽  
Binder Ratio ◽  
Water Binder Ratio

In this study conventional concrete of M40 grade developed with diverse water binder ratio and fixed optimum dosage of 30% mineral admixture fly ash and GGBS with weight of cement .Compression test has been conducted on cube samples and Rapid Chloride permeability test (RCPT) are conducted on cylindrical specimens to acknowledge durability parameter. Compression test results has been enhanced with replacement of supplementary cementitious materials and chloride ion permeability has been reduced with substitution of fly ash and GGBS .incremental of water binder ratio also reduce the permeability value however compression value increased

scholarly journals Experimental Study and Simulation Calculation of the Chloride Resistance of Concrete under Multiple Factors

2021 ◽  
Vol 11 (12) ◽  
pp. 5322
Author(s):  
Yang Ding ◽  
Tong-Lin Yang ◽  
Hui Liu ◽  
Zhen Han ◽  
Shuang-Xi Zhou ◽  
...  
Keyword(s):  
Hydrostatic Pressure ◽  
Penetration Depth ◽  
Chloride Ion ◽  
Cementitious Materials ◽  
Chloride Ions ◽  
Finite Element Software ◽  
Chloride Resistance ◽  
Simulation Calculation ◽  
Marine Concrete ◽  
Resistance Performance

Cement is widely used in marine concrete, and its resistance to chloride ion corrosion has been widely considered. In this paper, based on a laboratory test, the influence of different hydrostatic pressures, coarse aggregate contents and w/c ratios on the chloride resistance performance is analyzed. Based on COMSOL finite element software, a two-dimensional cementitious materials model is established, and the simulation results are compared with the experimental results. The results show that the penetration depth of chloride ions in cement increases with the increase of the w/c ratio. Under the hydrostatic pressure of 0 MPa, when the w/c ratio is 0.35, the penetration depth of chloride ions is 7.4 mm, and the simulation result is 8.0 mm. When the w/c ratio is 0.45, the penetration depth of chloride ions is 9.3 mm, and the simulation result is 9.9 mm. When the w/c ratio is 0.55, the penetration depth of chloride ions is 12.9 mm, and the simulation result is 12.1 mm. Under different hydrostatic pressures, the penetration depth of chloride ions obviously changes, and with the increase in hydrostatic pressure, the penetration depth of chloride ions deepens. Under the w/c ratio of 0.35, when the hydrostatic pressure is 0.5 MPa, the penetration depth of chloride ions is 11.3 mm, and the simulation result is 12.1 mm. When the hydrostatic pressure is 1.0 MPa, the penetration depth of chloride ions is 16.2 mm, and the simulation result is 17.5 mm.

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