Chlorine Ion Penetration Resistance of Concretes Containing Super-Fine Limestone Powder

2012 ◽  
Vol 512-515 ◽  
pp. 2961-2964
Author(s):  
Hong Fang Li ◽  
Yi Xia
Keyword(s):  
Penetration Resistance ◽  
Limestone Powder ◽  
Curing Time ◽  
Key Factor ◽  
Binder Ratio ◽  
Chlorine Ion ◽  
Penetration Tests ◽  
Water Binder Ratio ◽  
Ion Penetration

The influence of limestone powder, air-entraining agent and water binder ratio on chlorine ion (Cl-) penetration resistance of concretes was investigated by rapid Cl- penetration tests. The results show that the fineness of limestone powder is a key factor to Cl- penetration resistance of concrete. It can improve Cl- penetration resistance by introducing super fine limestone powder into concrete. Cl- penetration resistance of concrete increases as curing time increases. The concrete with lower water binder ratio has better Cl- penetration resistance. The introduction of air-entraining agent into concrete can enhance Cl- penetration resistance by improving micro pores structure. The optimum mixing amount is 0.3‰.

scholarly journals The Rapid Chloride Migration Test in Assessing the Chloride Penetration Resistance of Normal and Lightweight Concrete

2021 ◽  
Vol 11 (16) ◽  
pp. 7251
Author(s):  
Jorge Pontes ◽  
José Alexandre Bogas ◽  
Sofia Real ◽  
André Silva
Keyword(s):  
Lightweight Concrete ◽  
Chloride Transport ◽  
Penetration Resistance ◽  
Chloride Penetration ◽  
Migration Test ◽  
Simple Method ◽  
Chloride Migration ◽  
Binder Ratio ◽  
Chloride Penetration Resistance ◽  
Water Binder Ratio

Chloride-induced corrosion has been one of the main causes of reinforced concrete deterioration. One of the most used methods in assessing the chloride penetration resistance of concrete is the rapid chloride migration test (RCMT). This is an expeditious and simple method but may not be representative of the chloride transport behaviour of concrete in real environment. Other methods, like immersion (IT) and wetting–drying tests (WDT), allow for a more accurate approach to reality, but are laborious and very time-consuming. This paper aims to analyse the capacity of RCMT in assessing the chloride penetration resistance of common concrete produced with different types of aggregate (normal and lightweight) and paste composition (variable type of binder and water/binder ratio). To this end, the RCMT results were compared with those obtained from the same concretes under long-term IT and WDT. A reasonable correlation between the RCMT and diffusion tests was found, when slow-reactive supplementary materials or porous lightweight aggregates surrounded by weak pastes were not considered. A poorer correlation was found when concrete was exposed under wetting–drying conditions. Nevertheless, the RCMT was able to sort concretes in different classes of chloride penetration resistance under distinct exposure conditions, regardless of the type of aggregate and water/binder ratio.

Application of Sulfoaluminate Cement for Solidification/Stabilization of Fly Ash from Municipal Solid Waste Incinerators

2012 ◽  
Vol 178-181 ◽  
pp. 795-798 ◽  
Author(s):  
Qi Na Sun ◽  
Jing Miao Li ◽  
Bao Quan Huo ◽  
Ji Bing Wang
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Municipal Solid Waste ◽  
Solid Waste ◽  
High Performance ◽  
Curing Time ◽  
Leaching Toxicity ◽  
Binder Ratio ◽  
Waste Incinerators ◽  
Water Binder Ratio

Sulfoaluminate cement (SAC) was utilized for the solidification/stabilization of fly ash from municipal solid waste (MSW) incinerators. The effects of fly ash amount and water/binder ratio were investigated on compressive strength and heavy metals leaching toxicity of solidified matrices at different curing times. The results showed that prolonged curing time, lower fly ash amount and water/binder ratio enhanced the compressive strength and decreased the leaching concentrations of Zn, Pb and Cu. For 28 days cured matrices with fly ash amount 50% and water/binder ratio 0.30, the compressive strength was 32.6 MPa and the leaching concentrations of Zn, Pb and Cu were 14.73, 0.75 and 0.43 mg/L respectively. The leaching concentrations of Zn, Pb and Cu met the demand of GB 5085.3-2007. SAC is proved to be effective for MSW incinerator fly ash solidification/stabilization and high performance matrices for disposal and reuse may be achieved with further formula optimization.

Properties of Aerial Lime-Based Mortars with Chitosan Ethers

2018 ◽  
Vol 276 ◽  
pp. 75-82 ◽  
Author(s):  
Tomáš Žižlavský ◽  
Martin Vyšvařil ◽  
Patrik Bayer ◽  
Pavla Rovnaníková
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Compressive Strength ◽  
Carboxymethyl Chitosan ◽  
Curing Time ◽  
Chitosan Derivatives ◽  
Early Stages ◽  
Binder Ratio ◽  
The Difference ◽  
Water Binder Ratio

This paper studies the possibility of usage of chitosan derivatives (hydroxypropyl chitosan (HPCH) and carboxymethyl chitosan (CMCH)) as admixtures for aerial lime-based mortars. The physical-mechanical properties were studied on the specimens prepared with constant water/binder ratio and binder/aggregate ratio 1:3 by weight using siliceous sand with the grain size up to 4 mm and doses of admixture ranging between 0.5 and 10‰. The properties were studied on the specimens up to 365 days. The addition of admixtures improves workability of mortar, but in the early stages also decreases strengths of mortars, especially the compressive strength. The addition of HPCH significantly reduces the bulk densities of specimens, while CMCH decreases them just slightly. With the increasing amount of time, the difference in strengths between reference and tested mortars decreases, reaching the similar values after 90 days of curing time. The further ageing causes additional growth of strengths with a significantly higher increase in the case of CMCH.

Penetration Resistance to Chloride Ions of Silica Fume Concrete

2014 ◽  
Vol 584-586 ◽  
pp. 1519-1522
Author(s):  
Yun Feng Li ◽  
Xiao Peng Fan ◽  
Lei Wen Gao ◽  
Ying Tao Li
Keyword(s):  
Silica Fume ◽  
Concrete Structures ◽  
Penetration Resistance ◽  
Chloride Ions ◽  
Factors Affecting ◽  
Binder Ratio ◽  
Water Binder Ratio ◽  
Durability Of Concrete

The penetration resistance to chloride ions of concrete is one of the important factors affecting the durability of concrete structures. The penetration resistance to chloride ions of concrete is measured with the increasing substitution amount of silica fume in this paper. For the low water-binder ratio of 0.28, 0.30 and 0.32, compared with the reference concrete, with the increase of age, the penetration resistance to chloride ions of concrete can be enhanced with the increasing substitution amount of silica fume, but the increased range is smaller. The penetration resistance of chloride ions of concrete is not necessarily improved by gradually decreasing the water-binder ratio. Considering the substitution amount of silica fume, water-binder ratio and concrete age, the best mix proportions are that the substitution amount of silica fume is 9% or 12% when the water-binder ratio is 0.28 and the substitution amount of silica fume is 12% when the water-binder ratio is 0.30.

Properties of Concrete with High-Volume Limestone Powder under Low Temperature Conditions

2013 ◽  
Vol 675 ◽  
pp. 296-301
Author(s):  
Shao Min Song ◽  
Wen Zhong Bao ◽  
Wen Xin Zhao ◽  
Dong Min Jin
Keyword(s):  
Fly Ash ◽  
Low Temperature ◽  
High Volume ◽  
Sulfate Solution ◽  
Active Role ◽  
Mineral Admixture ◽  
Limestone Powder ◽  
Strength Development ◽  
Binder Ratio ◽  
Water Binder Ratio

This paper studies the effects of high-volume composite mineral admixture made of limestone powder and low-quality fly ash on the properties of concrete,and studies the form of attack of cement-based material made of limestone powder at low water-binder ratio under low-temperature sulfate environment.Through experiments, this paper makes clear the workability of fresh concrete and analyzes the law of strength development of concrete. The experimental results indicate that the concrete with high-volume limestone powder as composite mineral admixture has good fresh properties; due to low water consumption per unit volume, medium-and-high-strength concrete can be prepared. As new type concrete mineral admixture, the composite mineral admixture made of limestone powder and low-quality fly ash will play an active role in the sustainable development of concrete industry. After the specimen with the water-binder ratio of less than 0.4 and the limestone powder volume of greater than 20% is soaked in 10% magnesium sulfate solution at low temperature at the age of 200d, gypsum attack-led destruction is caused to the concrete test cube, without thaumasite sulfate attack.

Study of the Effective Curing Parameter for Pre-Cast Concrete

2012 ◽  
Vol 174-177 ◽  
pp. 109-112
Author(s):  
Ming Fang Ba ◽  
Chun Xiang Qian
Keyword(s):  
Structural Characteristics ◽  
Curing Time ◽  
Steam Curing ◽  
X Ray ◽  
Binder Ratio ◽  
Cast Concrete ◽  
Water Curing ◽  
Effective Water ◽  
Water Binder Ratio

The effective initial steam-curing and water-curing duration on concrete with lower water-binder ratio were investigated with XRD, TG-DSC, X-ray CT, SEM-BSE and MIP techniques. According to the effects of initial curing on the micro-structural characteristics of the pre-cast concrete, the effective steam curing duration is 10-14 hours and the effective water curing time was determined not to be over 7 days.

scholarly journals Research on the Chloride Ion Penetration Resistance of Magnesium Phosphate Cement (MPC) Material as Coating for Reinforced Concrete Structures

Coatings ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1145
Author(s):  
Yubing Du ◽  
Peiwei Gao ◽  
Jianming Yang ◽  
Feiting Shi
Keyword(s):  
Portland Cement ◽  
Basalt Fiber ◽  
Chloride Ion ◽  
Penetration Resistance ◽  
Magnesium Phosphate ◽  
Accelerated Corrosion ◽  
Chloride Ion Penetration ◽  
Chlorine Ions ◽  
Chlorine Ion ◽  
Ion Penetration

This study focuses on the chloride ion penetration resistance of a magnesium phosphate cement (MPC)-based composite material coating on the surface of silicate material. By means of electrical flux method and electric acceleration corrosion tests, the anti-chlorine ion permeation and reinforcement properties of MPC-based materials and Portland cement (OPC) mortar were compared and analyzed. The experimental results show that the electrical flux of the hardened body of the MPC-based material is much lower than that of the Portland cement mortar, and the electrical flux of the hardened body of the MPC mortar can be obviously reduced by adding silica-fume (SF) and fly ash (FA), which, when combined in a suitable proportion, will make the MPC’s hardened body more dense and impermeable. The addition of short cut fibers increases the number of pores, the pore size, and the electrical flux of the cement mortar’s hardened body. The adverse effects of the three fibers on the permeability of the MPC mortar against chlorine ions were as follows: polyvinyl alcohol fiber > glass fiber > basalt fiber. The electrical flux of MPC mortar or MPC paste coated on the surface of the OPC mortar was greatly reduced. Compared with silicate mortar, the MPC-based material has excellent protective performance under the condition of accelerated corrosion.

Performance of Compound Cementitious Material Compounded with Clinker and Limestone Powder and Coal Ash

2011 ◽  
Vol 477 ◽  
pp. 142-147
Author(s):  
Tian Yong Huang ◽  
Yun Fen Hou
Keyword(s):  
Compressive Strength ◽  
Flexural Strength ◽  
Coal Ash ◽  
Cementitious Material ◽  
Limestone Powder ◽  
Mortar Strength ◽  
Cleavage Strength ◽  
Binder Ratio ◽  
Water Amount ◽  
Water Binder Ratio

Limestone powder and coal ash are selected to prepare compound cementitious material with clinker. It is found that with the increasing of mixture (including limestone powder and coal ash), the water amount for standard consistency of compound cementitious material increases and the flexural strength and compressive strength at 3 and 28 days decrease. Increasing of limestone powder can reduces the water amount for standard consistency. The compressive strength, flexural strength and cleavage strength decrease with the increasing of mixture. If the mixture dosage is 60%, when the ratio of limestone powder and coal ash is 8:2, the compressive strength is the highest. If the mixture dosage increases to 70%, when the ratio of limestone powder and coal ash is 7:3, the compressive strength is the highest. If the mixture dosage is 80%, the all strengths are very low. The compressive strength increases significantly with time, the compressive strength is greater than 50MPa at 90 days. Although the mortar strength of compound cementitious material is far below for mortar strength required by cement standard, but the middle-low strength grade concrete can be prepared by low water-binder ratio.

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