scholarly journals Fundamental Study on Low-Temperature Autoclaving Focused on the Water Cement Ratio and Silica Fume Content

2013 ◽  
Vol 62 (10) ◽  
pp. 615-620 ◽  
Author(s):  
Shin YAMAGUCHI ◽  
Masami UZAWA ◽  
Naofumi IWASAKI ◽  
Yoji OGAWA ◽  
Yoshinari ITOH ◽  
...  
Keyword(s):  
Low Temperature ◽  
Silica Fume ◽  
Fundamental Study ◽  
Cement Ratio ◽  
Water Cement Ratio

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]

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.

Effects of Temperature on Drying Shrinkage of Concrete

2014 ◽  
Vol 584-586 ◽  
pp. 1176-1181 ◽  
Author(s):  
Ying Zi Yang ◽  
Mao Guang Li ◽  
Hong Wei Deng ◽  
Qi Liu
Keyword(s):  
Fly Ash ◽  
Silica Fume ◽  
Drying Shrinkage ◽  
Shrinkage Strain ◽  
Mineral Admixture ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Granulated Blast Furnace Slag ◽  
Influence Of Water ◽  
Effects Of Temperature

The present study investigated experimentally effects of temperature on drying shrinkage of concrete in different water cement ratio and containing mineral admixture. Concrete was exposed to a controlled environment of 20±1oC, 35±1oC, 50±1oC, and 60% ± 5 RH, respectively. The drying shrinkage of concretes with water cement ratio of 0.3, 0.4 and 0.5 were evaluated. The resuluts showed that with the increase of temperature from 20 oC to 50 oC, the influence of water cement ratio on drying shrinkage of concrete was gradually weakened. The shrinkage strain of concretes with replacement of cement by 20% of ground granulated blast-furnace slag (GGBS), 10% of silica fume (SF), and 20% of fly ash (FA) were measured, respectively. Test results showed that GGBS had a little impact on drying shrinkage of concrete; Silica fume could increase the drying shrinkage of concrete significantly in the early and later ages, especially when concrete was subjected to high temperature; Fly ash reduced drying shrinkage in early ages and increased drying shrinkage of concrete in the later ages.

Coefficient of Linear Expansion of Air-Entraining Concrete with Silica Fume

2010 ◽  
Vol 168-170 ◽  
pp. 2116-2120
Author(s):  
Jian Chao Dou ◽  
Jian Sen Yang
Keyword(s):  
Compressive Strength ◽  
Silica Fume ◽  
Linear Expansion ◽  
Content Increase ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Air Content ◽  
Effect Of Water ◽  
Compressive Strength Of Concrete ◽  
Coefficient Of Linear Expansion

The effect of water-cement ratio, air content, silica fume and sand ratio of concrete on the coefficient of linear expansion(CLE) was studied by orthogonal experiment. The results show that under a certain amount of cement material, CLE of concrete increase as the water-cement ratio increases and the effect of water-cement ratio on CLE of concrete is remarkable; with the increase of blending ratio of silica fume, the CLE of concrete increases; the CLE of concrete reduces with 3.5% air content in concrete, but rebound with 6% air content in concrete; with the sand rate increases, CLE of concrete increases; CLE per unit compressive strength of concrete with silica fume decreases with increase of silica fume content; CLE per unit compressive strength of concrete with air content increase when air content increase.

scholarly journals Effects of Using Silica Fume and Polycarboxylate-Type Superplasticizer on Physical Properties of Cementitious Grout Mixtures for Semiflexible Pavement Surfacing

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Suhana Koting ◽  
Mohamed Rehan Karim ◽  
Hilmi Mahmud ◽  
Nuha S. Mashaan ◽  
Mohd Rasdan Ibrahim ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Silica Fume ◽  
High Strength ◽  
Flexible Pavement ◽  
Cementitious Materials ◽  
Flow Properties ◽  
Cement Ratio ◽  
Paired Sample ◽  
Water Cement Ratio ◽  
Porous Pavement

Semi-flexible pavement surfacing is a composite pavement that utilizes the porous pavement structure of the flexible bituminous pavement, which is subsequently grouted with appropriate cementitious materials. This study aims to investigate the compressive strength, flexural strength, and workability performance of cementitious grout. The grout mixtures are designed to achieve high strength and maintain flow properties in order to allow the cement slurries to infiltrate easily through unfilled compacted skeletons. A paired-samplet-test was carried out to find out whether water/cement ratio, SP percentages, and use of silica fume influence the cementitious grout performance. The findings showed that the replacement of 5% silica fume with an adequate amount of superplasticizer and water/cement ratio was beneficial in improving the properties of the cementitious grout.

Study on the Frost Resistance of Artificial Aggregates Recycled Concrete

2012 ◽  
Vol 509 ◽  
pp. 82-87
Author(s):  
Jin Bang Wang ◽  
Zong Hui Zhou
Keyword(s):  
Elastic Modulus ◽  
Fly Ash ◽  
Silica Fume ◽  
Frost Resistance ◽  
Mechanical Performance ◽  
Recycled Concrete ◽  
Dynamic Elastic Modulus ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Freeze Thaw

The recycled concrete was prepared by using the high-strength artificial aggregates. This kind of concrete can be completely regenerated to be cement, and the recycling utilization of the concrete can also be truly realized. The frost resistance and influencing factors of the recycled concrete were studied. The results show that the mechanical performance and frost resistance of artificial aggregates recycled concrete are better than those of the ordinary concrete under the same water/cement ratio condition. When the water/cement ratio is 0.40, the relative dynamic elastic modulus, weight loss and frost durability factor of the recycled concrete are 98.7%, 0.5% and 65.8 after 200 times freeze-thaw cycles. When the fly ash and silica fume were added into the recycled concrete, the frost resistance can be improved. The optimal amounts of fly ash and silica fume are 30% and 15% of cement by weight, respectively. The recycled concrete was prepared with the optimal fly ash and silica fume content, respectively. After 200 times freeze-thaw cycles, the relative dynamic elastic modulus of the recycled concrete are 99.1% and 99.2%, and the weight losses of the recycled concrete are 0.4% and 0.3%, and antifreeze durability coefficient of the recycled concrete are 66.07 and 66.13. Therefore, the recycled concrete with silica fume has better frost resistance performance than that with fly ash as admixture.

scholarly journals Early Hardening Process of CA Mortar Indicated by Electrical Resistivity

2020 ◽  
Author(s):  
Tao Wang ◽  
Hengqiong Jia ◽  
Shaoliang Wu ◽  
Zhao Wei ◽  
Xiao Xie ◽  
...  
Keyword(s):  
Electrical Resistivity ◽  
Induction Period ◽  
Silica Fume ◽  
Resistivity Measurement ◽  
Electrical Resistivity Measurement ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Hardening Process ◽  
Early Strength ◽  
Ca Mortar

A non-contact electrical resistivity measurement device was employed to indicate the early hardening process of cement asphalt emulsified mortar (CA mortar). It was found that this process was analogous with the hydration process of cement and could be categorized into three parts: dissolving period, induction period and setting period. The mortar resistivity first decreased and then increased with the elapsed time. The effect of water/cement ratio (W/C), asphalt emulsified/cement ratio (A/C), cement types were also explored. Results indicated that the increase of W/C, dosages in SF (Silica fume) extended the induction period; replacement of Portland cementII with sulfoaluminate cement in CA mortar markedly increased the electrical resistivity and advanced the onset of setting period by 5∼6 h, making it possible to prepare CA mortar with high early strength, which can preventing distress such as peeling and bleeding during construction in winter and conformance to requirements in acceptance standard.

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