Study on Chloride Penetration Resistance of High Volume Slag Powder Concrete

2014 ◽  
Vol 584-586 ◽  
pp. 1005-1010
Author(s):  
Hong Xia Ding ◽  
Chun Tao Wang ◽  
Bin Ge ◽  
Yun Sheng Li
Keyword(s):  
Portland Cement ◽  
Chloride Ion ◽  
High Volume ◽  
Penetration Resistance ◽  
Chloride Penetration ◽  
Portland Cement Concrete ◽  
Cement Concrete ◽  
Slag Powder ◽  
Chloride Penetration Resistance ◽  
Electric Flux

The influences of Portland cement substituted by slag powder in a high proportion (50% and 70%) on the chloride penetration resistance of concrete were studied. The results show that: the penetrability of Portland cement concrete reduced by one grade if 0.5% water reducer is added, but the water binder ratio is not the decisive factor for the permeability. There is a negative correlation between 6h electric flux and compressive strength only when concrete with same cementing materials. High volume slag powder concrete has excellent resistance to chloride ion permeability, which declines further with the increment of slag powder quantity added, the permeability coefficient of the concrete with 50% and 70% content of slag powder is as low as 27.8%~32.3% that of Portland cement concrete.

Enhanced Portland Cement Concrete Fatigue Model for StreetPave

2005 ◽  
Vol 1919 (1) ◽  
pp. 29-37 ◽  
Author(s):  
Leslie Titus-Glover ◽  
Jagannath Mallela ◽  
Michael I. Darter ◽  
Gerald Voigt ◽  
Steve Waalkes
Keyword(s):  
Portland Cement ◽  
Stress Ratio ◽  
Design Method ◽  
High Volume ◽  
Fatigue Tests ◽  
Slab Thickness ◽  
Portland Cement Concrete ◽  
Cement Concrete ◽  
Fatigue Model ◽  
Pavement Thickness

The Portland Cement Association (PCA) pavement thickness design method for jointed concrete pavements is mechanistically based and consists of both fatigue and erosion analyses. It determines the minimum slab thickness required for a given set of site and design conditions on the basis of both fatigue and erosion criteria. At the heart of the fatigue analysis is the fatigue model, which establishes the number of allowable load repetitions for a given stress ratio [ratio of flexural edge stress caused by the application of wheel loads to the portland cement concrete (PCC) slab flexural strength]. The PCA fatigue model is based on data derived from beam fatigue tests conducted in the early 1950s and 1960s. The model estimates the conservative lower-bound estimate of the allowable number of load applications at a given stress ratio (i.e., it incorporates a high degree of reliability–-approximately 90% or higher). Although this may be desirable for high-volume, high-traffic pavements, it is too conservative for low-volume roads or street pavements. The PCA pavement thickness design method currently is being used in the American Concrete Pavement Association (ACPA) pavement design software, StreetPave. StreetPave incorporates the PCA's pavement thickness design methodology in a Windows-based user platform. ACPA commissioned a study to expand, improve, and broaden the current PCA fatigue model by including reliability as a parameter for predicting PCC fatigue damage and by calibrating the enhanced model with additional fatigue data from recently completed studies. An enhanced fatigue model was then developed.

Chloride Ion Diffusion of Phosphoaluminate Cement Concrete

2009 ◽  
Vol 79-82 ◽  
pp. 99-102 ◽  
Author(s):  
Zhu Ding ◽  
Feng Xing ◽  
Ming Zhang ◽  
Peng Liu
Keyword(s):  
Portland Cement ◽  
Chloride Ion ◽  
Chloride Ions ◽  
Hydration Products ◽  
Portland Cement Concrete ◽  
Ion Diffusion ◽  
Cement Concrete ◽  
Dense Microstructure ◽  
Corrosion Of Steel ◽  
Chloride Ion Diffusion

Penetration and diffusion of chloride ions in concrete can lead to the corrosion of steel bar and shorten the service life of concrete structures. Phosphoaluminate cement (PAC) is a new cementitious material which has many special properties compared to Portland cement (PC). In the study, chloride ion diffusion in PAC concrete was tested with RCM method. The phase composition and morphology of hydration products, pore volume of hardened paste cured for 28d were analyzed with X-ray diffraction (XRD) and mercury intrusion porosimetry (MIP). The results show that chloride ion diffusion coefficient of PAC concrete is much lower than that of Portland cement concrete under the same test conditions. The hydration products of PAC are main micro-crystalline phase and gel of phosphate and/or phophoaluminate, which formed a dense microstructure. There is no calcium hydroxide produced in the PAC hydration system. In hardened PAC paste, chloride ions might replace the atom group [OH] - and [PO4]3- of hydrates and become stable compounds. The resistance to chloride ion diffusion of PAC concrete will increase with the hydration age, because its microstructure becomes denser with the hydration age increasing.

High-Volume Fly Ash Concrete for Sustainable Construction

2012 ◽  
Vol 512-515 ◽  
pp. 2976-2981 ◽  
Author(s):  
Jeffery S. Volz
Keyword(s):  
Fly Ash ◽  
Portland Cement ◽  
High Volume ◽  
Sustainable Construction ◽  
Portland Cement Concrete ◽  
Cement Concrete ◽  
Fly Ash Concrete ◽  
Worldwide Production ◽  
High Volume Fly Ash ◽  
Green Solution

With worldwide production of fly ash approaching 800 million tonnes annually, increasing the amount of fly ash used in concrete will remove more material from the solid waste stream and reduce the amount ending up in landfills. However, most specifications limit the amount of cement replacement with fly ash to less than 25 or 30%. Concrete with fly ash replacement levels of at least 50% – referred to as high-volume fly ash (HVFA) concrete – offers a potential green solution. The following study investigated the structural performance of HVFA concrete compared to conventional portland-cement concrete. Specifically, the research examined both the bond strength of reinforcing steel in HVFA concrete as well as the shear behavior of HVFA reinforced concrete. The results indicate that HVFA concrete performs as well or better than conventional portland-cement concrete.

Performances of Belite-Rich Cement Concrete with Fly Ash and Phosphorous Slag Powder

2012 ◽  
Vol 174-177 ◽  
pp. 1502-1506
Author(s):  
Hua Shan Yang ◽  
Sheng Jin Tu ◽  
Yin Long Jin ◽  
Wang Tao
Keyword(s):  
Fly Ash ◽  
Portland Cement ◽  
Outdoor Exposure ◽  
Hydration Heat ◽  
Strength Development ◽  
Portland Cement Concrete ◽  
Cement Concrete ◽  
Slag Powder ◽  
Exposure Site ◽  
Phosphorous Slag

This paper presents the results of laboratory and outdoor exposure site studies on belite-rich cement concrete with phosphorous slag powder and fly ash. The parameters studied included strength, hydration heat, ultimate elongation, Young’s modulus, and adiabatic in temperature. The experimental results showed that belite-rich cement resulted in a higher rate of strength development of mortar and concrete at later ages when compared with that of moderate-heat Portland cement. And the hydration heat of belite-rich cement is lower than that of reference. This is due to the different phase composition of the two cements. Belite-rich cement contains less C3S but more C2S than moderate-heat Portland cement. In addition, belite-rich cement concrete with phosphorous slag powder and fly ash exhibited better performances than those of moderate-heat Portland cement concrete.

scholarly journals Effect of graphene oxide on chloride penetration resistance of recycled concrete

2019 ◽  
Vol 8 (1) ◽  
pp. 681-689 ◽  
Author(s):  
Kai Guo ◽  
Hang Miao ◽  
Lin Liu ◽  
Jinghai Zhou ◽  
Ming Liu
Keyword(s):  
Graphene Oxide ◽  
High Strength ◽  
Penetration Resistance ◽  
Chloride Penetration ◽  
Recycled Concrete ◽  
Volume Stability ◽  
Micro Cracks ◽  
Structure Morphology ◽  
Chloride Penetration Resistance ◽  
Electric Flux

Abstract Graphene oxide (GO) is a nanomaterial with ultra-high strength, good hydrophilicity, and dispersibility. To study the effect of GO on chloride penetration resistance of recycled concrete, the mechanism of action is investigated. The electric flux method is used to test the chloride penetration in recycled concrete specimens with 0, 0.03%, 0.06%, and 0.09% of GO. The volume change, microscopic pore distribution, and micro-structure morphology are characterized using laser rangefinder, and techniques such as X-ray tomography and scanning electron microscopy. The results show that the "coagulation nodule" effect of GO provides a growth basis for cement hydration,which results in a more uniform distribution of the hydrate microcrystals. It fills the micro-cracks of the recycled concrete, reduces the most probable aperture, increases the number of harmless small apertures, and enhances the volume stability of recycled concrete, thereby improving the chloride penetration resistance, which is important for improving the durability of concrete.

scholarly journals EVALUATION OF CONCRETE RESISTANCE TO CHLORIDE IONS PENETRATION BY MEANS OF ELECTRIC RESISTIVITY MONITORING

2005 ◽  
Vol 11 (2) ◽  
pp. 109-114 ◽  
Author(s):  
Marta Kosior-Kazberuk ◽  
Walery Jezierski
Keyword(s):  
Portland Cement ◽  
Salt Solution ◽  
Chloride Ion ◽  
Chloride Ions ◽  
Chloride Salt ◽  
Test Results ◽  
Ion Permeability ◽  
Portland Cement Concrete ◽  
Cement Concrete ◽  
Concrete Resistivity

The chloride‐induced corrosion of reinforcing steel is the major reason for the premature deterioration and degradation of field concrete structures built in a salt‐laden environment. The results of investigation of the bituminous addition effect on Portland cement concrete resistance to chloride ions penetration are presented in this paper. Chloride penetration was simulated by subjecting samples to cyclic loading with salt solution and drying. Concrete resistivity development was monitored during 12 months. The test results have been analysed to verify the effect of addition content, the time of exposure in aggressive environment, as well as the sort of cement on chloride ion permeability of Portland cement concrete. The statistical analysis showed that bituminous addition significantly improves the concrete resistance to chloride salt solution penetration.

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