scholarly journals Mechanical and Durability Characteristics of Latex-Modified Fiber-Reinforced Segment Concrete as a Function of Microsilica Content

2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
Woong Kim ◽  
Ri-On Oh ◽  
Joo-Ha Lee ◽  
Mi-Sol Kim ◽  
Sang-Min Jeon ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Flexural Strength ◽  
Impact Resistance ◽  
Chloride Ion ◽  
Penetration Resistance ◽  
Synthetic Fiber ◽  
Fiber Reinforced ◽  
Synthetic Fibers ◽  
Chloride Ion Penetration ◽  
Ion Penetration

This study evaluated the performance of latex-modified fiber-reinforced concrete (RC) segments as a function of the substitution level of microsilica and type of reinforced fiber, to address the problem of corrosion of steel segments and steel-reinforced fiber segments, which are commonly used to shield tunnel-boring machine (TBM) tunnels in urban spaces. Our study compared macro synthetic, steel, and hybrid (macro synthetic fiber + polypropylene fiber) reinforcing fibers. The substitution levels of microsilica used were 0, 2, 4, and 6%. The target strengths were set at 40 and 60 MPa to test compressive strength, flexural strength, chloride ion penetration resistance, and impact resistance. Testing of latex-modified and fiber-reinforced segment concrete showed that the compressive strength, flexural strength, and chloride ion penetration resistance increased with an increasing substitution level of microsilica. These improvements were attributed to the densification of the concrete due to filling micropores with microsilica. Micro synthetic fiber was more effective in terms of improved compressive strength, flexural strength, and chloride ion penetration resistance than steel fiber. These results were due to the higher number of micro synthetic fibers per unit volume compared with steel fiber, which reduced the void volume and suppressed the development of internal cracks. The optimal microsilica content and fiber volume fraction of micro synthetic fiber were 6% and 1%, respectively. To evaluate the effects of the selected mixtures and hybrid fibers simultaneously, other mixing variables were fixed and a hybrid fiber mixture (combination of macro synthetic fibers and polypropylene fibers) was used. The hybrid fiber mixture produced better compressive strength, flexural strength, chloride ion penetration resistance, and impact resistance than the micro synthetic fibers.

Influence of Slag Fineness on Durability of High-Performance Concrete

2012 ◽  
Vol 204-208 ◽  
pp. 3240-3243
Author(s):  
Hui Liu ◽  
Ping Li ◽  
Qiao Lan Jin
Keyword(s):  
Compressive Strength ◽  
Surface Area ◽  
Frost Resistance ◽  
High Performance ◽  
High Performance Concrete ◽  
Chloride Ion ◽  
Penetration Resistance ◽  
Concrete Durability ◽  
Chloride Ion Penetration ◽  
Ion Penetration

This research focuses on investigating the high performance concrete durability containing slag with different fineness and dosage. For this purpose, the 28-day compressive strength, chloride ion penetration, and frost resistance were investigated, with slag surface area 420m2/kg, 530m2/kg, 610m2/kg, and 720m2/kg, and replacement percentage 0%, 20%, 40%, and 60%, respectively. It was found that chloride ion penetration resistance were affected by the fineness and dosage of slag, and concrete frost resistance property was mainly controlled by dosage of slag rather than the fineness, and the 28-day compressive strength increased with slag incorporation.

Influence of Slag Fineness on High-Performance Concrete Properties

2012 ◽  
Vol 174-177 ◽  
pp. 286-290
Author(s):  
Hui Liu ◽  
Yuan Bao Leng ◽  
Wan Zeng Song ◽  
Sheng Bi
Keyword(s):  
Compressive Strength ◽  
Surface Area ◽  
High Performance ◽  
High Performance Concrete ◽  
Chloride Ion ◽  
Penetration Resistance ◽  
Slag Surface ◽  
Concrete Properties ◽  
Chloride Ion Penetration ◽  
Ion Penetration

This research focuses on investigating the high performance concrete containing slag with different fineness and dosage. For this purpose, the workability, compressive strength at different ages, and chloride ion penetration were investigated, with slag surface area 420m2/kg, 530m2/kg, 610m2/kg, and 720m2/kg, and replacement percentage 0%, 20%, 40%, and 60%, respectively. It was found that the workability and chloride ion penetration resistance were affected by the fineness and dosage of slag. The 7-day compressive strength decreased with slag replacement increasing when the fineness of slag is lower than 530m2/kg, and 28-day and 56-day compressive strength increased; For the fineness higher than 530m2/kg, the 7-day compressive strength is higher than that of control concrete, when the slag replacement was 40%, the concrete reached the highest value, and the 28-day and 56-day compressive strength increased with slag incorporation.

scholarly journals Effect of steel fiber on impact resistance and durability of concrete containing nano-SiO2

2021 ◽  
Vol 10 (1) ◽  
pp. 504-517
Author(s):  
Peng Zhang ◽  
Hongsen Zhang ◽  
Guo Cui ◽  
Xiaodong Yue ◽  
Jinjun Guo ◽  
...  
Keyword(s):  
Impact Energy ◽  
Steel Fiber ◽  
Impact Resistance ◽  
Chloride Ion ◽  
Penetration Resistance ◽  
Freeze Thaw ◽  
Chloride Ion Penetration ◽  
The Impact ◽  
Durability Of Concrete ◽  
Ion Penetration

Abstract Impact drop weight tests, rapid chloride migration coefficient tests, single-sided freeze–thaw tests, and mechanical property tests were performed to investigate the effect of the steel fiber (SF) content on the impact resistance and durability of concrete containing nano-SiO2 (NS). A fixed NS content of 3% and six SF contents in a range of 0–2.5% by volume were used. The impact resistance was measured based on the number of blows (N1, N2) and the impact energy. The durability of concrete includes its freeze–thaw resistance and chloride ion penetration resistance, which were appraised by the chloride ion diffusion coefficient (CDC) and relative dynamic elastic modulus (RDM), respectively. The ductility ratio was used to predict the impact resistance of concrete containing NS with different SF contents, and a linear relation between this ratio and the impact energy (R 2 = 0.853) was found. The experimental results indicated that SF could greatly improve the impact resistance of concrete. The addition of 2.0% SF increased N1 and N2 by 106 and 169%, respectively. In addition, an appropriate SF content significantly improved the durability of the concrete, including its frost resistance (especially in the middle and late freezing–thawing cycles) and chloride ion penetration resistance. An SF content of 1.5% was the optimum, decreasing the CDC of nano-concrete by 17.1% and minimizing the RDM loss. Moreover, the 1.5% SF content increased the compressive strength of concrete containing NS by 18.5%, whereas an SF content of 2.0% increased the splitting tensile strength and flexural strength by 77 and 20%, respectively. Furthermore, when the SF content exceeded a certain value, the improvement effect on these properties began to decrease and even became negative.

Experimental Study on Sustainable Concrete with the Mixture of Low Calcium Fly Ash and Lime as a Partial Replacement of Cement

2011 ◽  
Vol 250-253 ◽  
pp. 307-312 ◽  
Author(s):  
Muthuramalingam Jayakumar ◽  
M. Salman Abdullahi
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Water Absorption ◽  
Chloride Ion ◽  
Apparent Volume ◽  
Partial Replacement ◽  
Fly Ash Concrete ◽  
Low Calcium ◽  
Chloride Ion Penetration ◽  
Ion Penetration

Even though the use of fly ash in concrete is nowadays a common practice, its relatively slow pozzolanic reactivity hinders its greater utilization; hence efficient methods of activation are on demand. This study was carried out to evaluate the influence of lime as a chemical activator on the mechanical and durability properties of high strength fly ash concrete. Mixtures were made with 0, 30, 40, and 50% of cement replaced by low calcium fly ash. Corresponding mixtures were also made with the same amount of fly ash and addition of 10% of lime to each mixture. For each concrete mixture, slump, compressive strength, water absorption, sorptivity, apparent volume of permeable voids, and resistance to chloride-ion penetration were measured. The results obtained showed that addition of lime improved the compressive strength significantly at all ages. The strength of all the fly ash mixtures containing lime surpassed that of the corresponding Portland cement mix at 60 days. Addition of lime also improved the sorptivity and resistance to chloride-ion penetration of the fly ash concrete. It however increases the water absorption and the volume of permeable voids of the fly ash concrete.

Research on Mechanical Property of Fiber-Reinforced Geopolymer

2012 ◽  
Vol 174-177 ◽  
pp. 757-760
Author(s):  
Qing Wang ◽  
Zhao Yang Ding ◽  
Jing Da ◽  
Zhi Tong Sui
Keyword(s):  
Mechanical Property ◽  
Compressive Strength ◽  
Flexural Strength ◽  
Polyvinyl Alcohol ◽  
Fiber Reinforced ◽  
Synthetic Fibers ◽  
Fiber Materials ◽  
Reinforcing Fiber ◽  
Better Than

The compatibility and mechanical property of two kinds of synthetic fibers to geopolymer were studied. Polyvinyl alcohol (PVA) and polypropylene (PP) were used as reinforcing fiber materials. The result shows that flexural strength of geopolymer is obviously increased by mixed with reinforcing fiber. PVA is better than PP in reinforcing the flexural strength, both of these fibers have no significant effect in reinforcing the compressive strength to geopolymer.

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