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.

Test to Fly Ash Recycled Concrete under Different Water Cement Ratio

2013 ◽  
Vol 303-306 ◽  
pp. 2606-2610
Author(s):  
Ming Zheng Chen ◽  
Xian Feng Liu ◽  
Lin Qing Huang
Keyword(s):  
Fly Ash ◽  
Performance Test ◽  
Mechanical Performance ◽  
Influence Factors ◽  
Engineering Application ◽  
Recycled Concrete ◽  
Recycled Aggregate ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Solid Foundation

The recovery and utilization to building solid waste is the current hot issues in the construction of towns. In this paper, 30 groups of fly ash recycled concrete test cube were designed and produced, through the mechanical performance test research, we analysised the main influence factors to the strength and performances of fly ash regeneration concrete test cube,such as recycled aggregate category, water cement ratio, the admix proportion of recycled aggregate. The test results would lay a solid foundation for the test research and engineering application of recycled concrete.

Studies the Properties of Polyaspartic Polyurea Coated Concrete under Coaction of Salt Fog and Freeze-Thaw

2012 ◽  
Vol 455-456 ◽  
pp. 781-785
Author(s):  
Ping Lu ◽  
Xin Mao Li ◽  
Xue Qiang Ma ◽  
Wei Bo Huang
Keyword(s):  
Elastic Modulus ◽  
Frost Resistance ◽  
Dynamic Elastic Modulus ◽  
Freeze Thaw ◽  
Decrease Rate ◽  
Thaw Cycle ◽  
Freeze Thaw Cycle ◽  
Salt Fog

. This paper mainly studied the properties of PAE polyurea coated concrete under coactions of salt fog and freeze-thaw. After exposed salt fog conditions for 200d, T3, B2, F2 and TM four coated concrete relative dynamic elastic modulus have small changes, but different coated concrete variation amplitude is different. T3 coated concrete after 100 times of freeze-thaw cycle the relative dynamic elastic modulus began to drop, 200 times freeze-thaw cycle ends, relative dynamic elastic modulus variation is the largest, decrease rate is 95%, TM concrete during 200 times freeze-thaw cycle, relative dynamic elastic modulus almost no change, B2 concrete and F2 concrete the extent of change between coating T3 and TM. After 300 times the freeze-thaw cycle coated concrete didn't appear freeze-thaw damage phenomenon. Four kinds of coating concrete relative dynamic elastic modulus variation by large to small order: T3 coated concrete > B2 coated concrete >F2 coated concrete > TM coated concrete, concrete with the same 200d rule. Frost resistance order, by contrast, TM coated concrete > B2 coated concrete > F2 coated concrete > T3 coated concrete.

scholarly journals Use of Silica Fume and GGBS to Improve Frost Resistance of ECC with High-Volume Fly Ash

2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Yushi Liu ◽  
Xiaoming Zhou ◽  
Chengbo Lv ◽  
Yingzi Yang ◽  
Tianan Liu
Keyword(s):  
Elastic Modulus ◽  
Sodium Chloride ◽  
Mass Loss ◽  
Frost Resistance ◽  
Chloride Solution ◽  
Sodium Chloride Solution ◽  
Tap Water ◽  
High Volume ◽  
Dynamic Elastic Modulus ◽  
Freeze Thaw

Fly ash (FA) has been an important ingredient for engineered cementitious composite (ECC) with excellent tensile strain capacity and multiple cracking. Unfortunately, the frost resistance of ECC with high-volume FA has always been a problem. This paper discusses the influence of silica fume (SF) and ground-granulated blast-furnace slag (GGBS) on the frost resistance of ECC with high volume of FA. Four ECC mixtures, ECC (50% FA), ECC (70% FA), ECC (30% FA + 40% SL), and ECC (65% FA + 5% SF), are evaluated by freezing-thawing cycles up to 200 cycles in tap water and sodium chloride solution. The result shows the relative dynamic elastic modulus and mass loss of ECC in sodium chloride solution by freeze-thaw cycles are larger than those in tap water by freeze-thaw cycles. Moreover, the relative dynamic elastic modulus and mass loss of ECC by freeze-thaw cycles increase with FA content increasing. However, the ECC (30% FA + 40% SL) shows a lower relative dynamic elastic modulus and mass loss, but its deflection upon four-point bending test is relatively smaller before and after freeze-thaw cycles. By contrast, the ECC (65% FA + 5% SF) exhibits a significant deflection increase with higher first cracking load, and the toughness increases sharply after freeze-thaw cycles, meaning ECC has good toughness property.

Research of Steel Fiber Self-Compacting Concrete Frost Resistance

2012 ◽  
Vol 174-177 ◽  
pp. 721-725 ◽  
Author(s):  
Ming Bao Gao ◽  
Yan Ru Zhao ◽  
Xiao Yan He
Keyword(s):  
Elastic Modulus ◽  
Frost Resistance ◽  
Steel Fiber ◽  
Concrete Specimen ◽  
Test Method ◽  
Dynamic Elastic Modulus ◽  
Self Compacting Concrete ◽  
Freeze Thaw ◽  
Thaw Cycle ◽  
Freeze Thaw Cycle

With the fast freeze-thaw test method, the c50 steel fiber self-compacting concrete was carried out 300 tests of freeze-thaw cycle. In the process of freeze-thaw cycles, it determined by the quality of the concrete specimen, dynamic elastic modulus and strength, and analyzed the steel fibers and their different contents on frost resistance of self-compacting concrete impact. The results showed that: steel fiber self-compacting concrete in freeze-thaw cycle can play constrained role in the quality loss, dynamic elastic modulus and intensity, and can significantly improve the self-compacting concrete frost resistance. Within a certain range, the more steel fiber, the stronger of frost resistance.

Experimental Study on the Splitting Tensile Strength of Recycled Concrete Made of Brick and Tile

2012 ◽  
Vol 166-169 ◽  
pp. 1521-1525
Author(s):  
Hui Wang ◽  
Ai Liang Zhai
Keyword(s):  
Experimental Study ◽  
Tensile Strength ◽  
Regression Analysis ◽  
Elastic Modulus ◽  
Splitting Tensile Strength ◽  
Recycled Concrete ◽  
Water Quantity ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Brick And Tile

By experimental, study on the elastic modulus and the splitting tensile strength together with the influence of the splitting tensile strength with different water-cement ratio, sand rate and water quantity , and the relational formula between the splitting tensile strength and the elastic modulus was summarized by regression analysis.

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.

Effect of Admixtures on Dynamic Elastic Modulus of Cement Paste at Early Age

2011 ◽  
Vol 261-263 ◽  
pp. 450-455
Author(s):  
Dong Hui Huang ◽  
Sheng Xing Wu ◽  
Xiao Jun Wang ◽  
Hai Tao Zhao
Keyword(s):  
Elastic Modulus ◽  
Cement Paste ◽  
Mechanical Response ◽  
Dynamic Elastic Modulus ◽  
Early Age ◽  
Concrete Technology ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Shrinkage Reducing Admixture ◽  
Nondestructive Testing Method

The elastic modulus of cement paste is the key parameter for characterizing the mechanical response of concrete. In modern concrete technology, the admixtures are often used to enhance the performance of concrete. This paper introduces a nondestructive testing method to evaluate the dynamic elastic modulus of cement paste. Moreover, the effect of water-cement ratio and conventional admixtures on the dynamic elastic modulus of cement paste is investigated, in which three kinds of admixtures are taken into account including Viscosity Modifying Admixture (VMA), Silica Fume (SF), and Shrinkage-Reducing Admixture (SRA). The results from experimental investigation indicate that the dynamic elastic modulus of cement paste increases with decreasing water-cement ratio. The addition of SF increases the dynamic elastic modulus, however, the overdosage of VMA causes its reduction. SRA reduces the elastic modulus at early age without affecting the elastic modulus at later period.

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