Behavior of high water-cement ratio concrete under biaxial compression after freeze-thaw cycles

2008 ◽  
Vol 23 (4) ◽  
pp. 589-594
Author(s):  
Huaishuai Shang ◽  
Yupu Song ◽  
Jinping Ou
Keyword(s):  
High Water ◽  
Biaxial Compression ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Freeze Thaw

Effect of Coarse Aggregate Types on the Microstructure of the ITZ and Durability of Concrete

2013 ◽  
Vol 838-841 ◽  
pp. 1801-1805 ◽  
Author(s):  
Li Juan Kong ◽  
Qing Chao Meng ◽  
Yuan Bo Du
Keyword(s):  
Rough Surface ◽  
Coarse Aggregate ◽  
High Water ◽  
Chloride Diffusion ◽  
Concrete Durability ◽  
Chloride Diffusion Coefficient ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Freeze Thaw ◽  
Limestone Aggregate

Influence of aggregate types on the impermeability and frost-resistance of concrete with different water/cement ratios were investigated, as well as the pore structure and hydrates of the ITZ. The results show that, concrete prepared with a high water/cement ratio and using granite aggregate, presents the highest values of chloride diffusion coefficient and the lowest numbers of freeze-thaw cycles. Whereas concrete prepared with a low water/cement ratio and using limestone aggregate, obtains the similar durability results. The limestone aggregate with a rough surface and higher water absorption, has a tight bonding with the cement paste. However, the granite and basalt aggregate that formed by magma eruption, have higher activity. The XRD results demonstrate that more clinkers participate in the hydration of cement, therefore, resulting in a denser ITZ. In order to improve the concrete durability, the basalt aggregate both with higher activity and rough surface is consider optimal.

scholarly journals Behavior of Plain Concrete of a High Water-Cement Ratio after Freeze-Thaw Cycles

Materials ◽  
2012 ◽  
Vol 5 (9) ◽  
pp. 1698-1707 ◽  
Author(s):  
Huai-Shuai Shang ◽  
Ting-Hua Yi ◽  
Yu-Pu Song
Keyword(s):  
Plain Concrete ◽  
High Water ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Freeze Thaw

Application of Neutron Radiography to Observe Water Absorbtion of Concrete

2010 ◽  
Author(s):  
P. Zhang ◽  
T. J. Zhao ◽  
L. S. Zhang ◽  
F. H. Wittmann ◽  
E. Lehmann ◽  
...  
Keyword(s):  
Spatial Resolution ◽  
High Spatial Resolution ◽  
Neutron Radiography ◽  
High Water ◽  
Moisture Distribution ◽  
Water Penetration ◽  
Capillary Suction ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Cement Based Materials

It has been experienced that service life of reinforced concrete structures is often limited due to lack of durability of cement-based materials. One major reason for this durability problem is the penetration of water and compounds dissolved in water into concrete. Therefore, there is an urgent need to study water penetration into concrete in order to better understand deterioration mechanisms. Neutron radiography provides an advanced non-destructive technique with high spatial resolution. In this contribution, neutron radiography was successfully utilized to study the process of water absorption of two types of concrete with different water-cement ratios namely 0.4 and 0.6. It is shown that it is possible to visualize migration of water into concrete and to quantify the time-dependent moisture distribution with accurately and with high spatial resolution by means of neutron radiography. In concrete with high water-cement ratio, water penetrates much quicker than in concrete with lower water cement ratio. Water penetration depth obtained from neutron radiography is in good agreement with corresponding values obtained from capillary suction tests. Experimental results obtained by means of neutron radiography on water penetration into concrete will be presented and discussed in this contribution. Results will provide us with a solid basis for a better understanding of deteriorating processes in concrete and other cement-based materials. These results may be considered to be a first step to improve durability of concrete.

Study on the Secondary Interface in Microstructure of the Superfine Sand Concrete

2014 ◽  
Vol 529 ◽  
pp. 112-116
Author(s):  
Yong Ning Mi ◽  
Xin Shao ◽  
Jin Ting Zhao ◽  
Zhen Guo Wang ◽  
Chuan Yue
Keyword(s):  
Compressive Strength ◽  
High Water ◽  
Interface Structure ◽  
Interface Microstructure ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
History Of ◽  
Calcium Silicon ◽  
Concrete Interface ◽  
Scanning Electron

The superfine sand concrete application in our country has a history of more than half a century. Although we have a certain understanding about the superfine sand concrete, there are few studies of superfine sand concrete interface. This experiment made up different water-cement ratio superfine sand concrete, and used scanning electron microscope to observe the secondary interface structure, the product of interface C-S-H gel had been carried on by the energy spectrum analysis. Results show that the secondary interface microstructure of the low water-cement ratio concrete is denser than high water cement ratio, and also have certain effects on macroscopic compressive strength; C-S-H gel calcium silicon ratio in the secondary interface is between 1.5 and 2.1.

Etude de la résistance au gel de bétons contenant un fluidifiant

1991 ◽  
Vol 18 (4) ◽  
pp. 581-589 ◽  
Author(s):  
Michel Pigeon ◽  
Marcel Langlois
Keyword(s):  
Silica Fume ◽  
Plain Concrete ◽  
Freezing And Thawing ◽  
Freezing Resistance ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Freeze Thaw ◽  
Spacing Factor ◽  
Thaw Cycle ◽  
Air Void

There is some controversy about freezing resistance of concrete containing superplasticizers. It has been quite convincingly demonstrated that, in some cases, such admixtures can significantly alter air-void systems in concrete. Some researchers believe, however, that concrete with superplasticizers can resist frost even when the air-void spacing factor is higher than the usual limit of 200 μm. The freeze–thaw cycle resistance tests described in this paper show that with the two types of concrete tested (a plain concrete with a water/cement ratio of 0.50 and a concrete with the same water/cement ratio but containing silica fume), the critical air-void spacing factor value is not significantly affected by the presence of a superplasticizer. When regular concrete is to be exposed to freeze–thaw conditions, the air-void system should meet the usual standards even when a superplasticizer is present. Key words: concrete, freezing and thawing, durability, superplasticizer, spacing factor, silica fume, water–cement ratio. [Journal translation]

Experimental Study of Mechanical Properties of Concrete after Freeze-Thaw Exposures

2014 ◽  
Vol 912-914 ◽  
pp. 131-135
Author(s):  
Xiang Ping Fu ◽  
Xiao Xue Liu ◽  
Yi Ze Sun ◽  
Pei Huang ◽  
Yu Chen Li ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Experimental Study ◽  
Compressive Strength ◽  
Elasticity Modulus ◽  
Concrete Specimen ◽  
Concrete Compressive Strength ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Freeze Thaw ◽  
Cold Area

The experiment studies how the freeze-thaw cycles influence concrete compressive strength and elasticity modulus with different water-cement ratio under the air-entraining agent and zero of that value respectively. It can be found that modulus of elasticity and compressive strength of the concrete specimen reduced significantly when there is air-entraining agent; the durability of freeze-thaw resistance, however, makes great improvement; as the cement increases, both of them improves effectively. Through the comparison of concrete compressive strength and elastic modulus with different water-cement ratio and air-entraining agent, the optimal water-cement ratio and air-entraining agent were determined. The results of experiment can be used in concrete engineering design in severe cold area.

La durabilité au gel des bétons à haute performance

1992 ◽  
Vol 19 (6) ◽  
pp. 975-980 ◽  
Author(s):  
Michel Pigeon ◽  
Richard Gagné ◽  
Pierre-Claude Aitcin ◽  
Marcel Langlois
Keyword(s):  
Silica Fume ◽  
Standard Procedure ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Freeze Thaw ◽  
Spacing Factor ◽  
Thaw Cycle ◽  
Entrained Air ◽  
Air Void ◽  
Limiting Value

Frost resistance of high-strength concrete (80–100 MPa) was studied by subjecting 44 concrete mixes to freeze–thaw cycles in water (ASTM C666, standard procedure A) and to scaling tests in the presence of deicer salts (ASTM C672, standard). The test programme was designed to analyze the effects of the water/cement ratio, the type of cement, the type of coarse aggregate, the duration of curing, and the air-void spacing factor. Results demonstrate that the water/cement ratio limiting value, below which entrained air is no longer necessary to protect concrete against freeze–thaw cycles, is sometimes higher than 0.30 but is more often below 0.25. This limiting value is affected most by cement characteristics: type 30 cement yielded much more durable concretes. Laboratory scaling tests demonstrated that when water/cement ratios are less than 0.30, the resistance deicer salt is generally very good, no matter what are the type of cement, the silica fume content, or the air-void spacing factor of the concrete. Key words: durability, freeze–thaw cycle, silica fume, scaling, curing, spacing factor, water/cement ratio, compressive strength, cement type, entrained air, aggregate. [Journal translation]

Study of RPC Mechanical Properties and Anti-Freeze-Thaw Resistance

2010 ◽  
Vol 168-170 ◽  
pp. 1742-1748
Author(s):  
Yan Zhong Ju ◽  
Feng Wang ◽  
De Hong Wang
Keyword(s):  
Mechanical Properties ◽  
Silica Fume ◽  
Steel Fiber ◽  
Fiber Content ◽  
Reactive Powder Concrete ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Freeze Thaw ◽  
Early Strength ◽  
Reactive Powder

To study the mechanical properties of RPC performance and freeze-thaw resistance，through the experimental study discussed the water-cement ratio, silica fume cement ratio, steel fiber content, curing system and other factors on the mechanical properties of reactive powder concrete and anti-freezing properties. Research indicates that many factors in the RPC, the water cement ratio is the most important factor, followed by the silica fume cement ratio, finally the steel fiber content, and curing system for the growth of its early strength also have a greater role.

scholarly journals Research on Influence of Water-Cement Ratio on Reinforcement Effect for Permeation Grouting in Sand Layer

2020 ◽  
Vol 2020 ◽  
pp. 1-12 ◽  
Author(s):  
Zhipeng Li ◽  
Lianzhen Zhang ◽  
Yuntian Chu ◽  
Qingsong Zhang
Keyword(s):  
Deformation Modulus ◽  
High Water ◽  
Sand Layer ◽  
Curing Time ◽  
Reinforcement Effect ◽  
Cement Slurry ◽  
Permeation Grouting ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Grouting Reinforcement

In order to study permeation grouting reinforcement effect in the sand layer, a set of grouting test device is developed, which consists of a power device, a pressure-bearing slurry tank, and several test frames. Compressive strength, deformation modulus, and permeability coefficient are selected to be the evaluation index of grouting reinforcement effect. Grouting reinforcement effect under different water-cement ratio of cement slurry and curing time were measured. Eventually, under laboratory conditions, fitting formulas have been obtained which describe the quantitative relationship between reinforcement effect of permeation grouting and water-cement ratio and curing time. Results show that water-cement ratio of slurry has obvious effect on grouting reinforcement effect. Mechanical performance and impermeability of the grouted body are negative-correlated with water-cement ratio. There are two different destruction patterns for the grouted body in uniaxial compression process: global destruction pattern at low water-cement ratio and local destruction pattern at high water-cement ratio. If cement slurry at high water-cement ratio is permeated into the sand layer, water bleeding phenomena will appear and lead to inhomogeneous performance of the grouted body, with lower performance in the upper part and higher performance in the lower part of the grouted body.

Efficiency Air-Entraining Water-Reducing Agent in Concrete Study on the Freeze-Thaw Resistance

2011 ◽  
Vol 71-78 ◽  
pp. 3566-3571 ◽  
Author(s):  
Mei Yan Hang ◽  
Wei Zhang
Keyword(s):  
Frost Resistance ◽  
Reducing Agent ◽  
Gas Content ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Freeze Thaw

In this paper, the frost resistance on different water-cement ratio of concrete after the air-entraining agent admixture. When the gas is controlled about 4%, with the lower water-cement ratio, freeze-thaw resistance of concrete is increased significantly. And then the frost resistance of YC20 and YC40 concrete which are mixed in efficient air-entraining water-reducing agent were studied, the experiment results that when the concrete YC40 reached F300, gas content reached more than 4.5%,and the strength without reducing, the durability would improve. But the YC20 is different, so, GL-B4-efficiency air-entraining water-reducing agent does not apply to the water-cement ratio above 0.6 of the concrete

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