scholarly journals Effect of Ultrafine Metakaolin on the Properties of Mortar and Concrete

Crystals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 665
Author(s):  
Shengli Zhang ◽  
Yuqi Zhou ◽  
Jianwei Sun ◽  
Fanghui Han
Keyword(s):  
Silica Fume ◽  
Chloride Ion ◽  
Cementitious Material ◽  
Concrete Sample ◽  
Curing Time ◽  
Sulphate Attack ◽  
Cement Concrete ◽  
Chloride Ion Penetration ◽  
Reference Samples ◽  
Better Than

This study investigated the influence of ultrafine metakaolin replacing cement as a cementitious material on the properties of concrete and mortar. Two substitution levels of ultrafine metakaolin (9% and 15% by mass) were chosen. The reference samples were plain cement concrete sample and silica fume concrete sample with the same metakaolin substitution rates and superplasticizer contents. The results indicate that simultaneously adding ultrafine metakaolin and a certain amount of polycarboxylate superplasticizer can effectively ensure the workability of concrete. Additionally, the effect of adding ultrafine metakaolin on the workability is better than that of adding silica fume. Adding ultrafine metakaolin or silica fume can effectively increase the compressive strength, splitting tensile strength, resistance to chloride ion penetration and freeze–thaw properties of concrete due to improved pore structure. The sulphate attack resistance of mortar can be improved more obviously by simultaneously adding ultrafine metakaolin and prolonging the initial moisture curing time.

Effects of Compositions on the Chloride Ion Permeability of Geopolymer Concrete

2012 ◽  
Vol 450-451 ◽  
pp. 428-432
Author(s):  
Qing Wang ◽  
Jing Da ◽  
Cun Bao Zhang ◽  
Zhao Yang Ding ◽  
Zhi Tong Sui
Keyword(s):  
Chloride Ion ◽  
Cementitious Material ◽  
Molar Ratio ◽  
Geopolymer Concrete ◽  
Ion Permeability ◽  
Flux Method ◽  
Molar Ratios ◽  
Electric Flux ◽  
Better Than

The three key oxide molar ratios of geopolymer concrete were studied in this paper: n(SiO2)/n(Al2O3)，n(Na2O)/n(Al2O3) and n(H2O)/n(Na2O). The effect of each oxide molar ratio was assessed by electric flux method. It was found that resistance to chloride ion of geopolymer was increased with increasing n(SiO2)/n(Al2O3).However, there was a limit beyond which this performance improved; it performed better with the increasing of n(Na2O)/n(Al2O3) but worse with the increasing of n(H2O)/n(Na2O). With the same amount of cementitious material, resistance to chloride ion of geopolymer concrete was better than that of common concrete.

Literature Review: Mechanical Properties of Hardened Silica Fume Concrete

2014 ◽  
Vol 1008-1009 ◽  
pp. 1357-1362
Author(s):  
Xi Xi He ◽  
Qing Wang
Keyword(s):  
Silica Fume ◽  
High Performance ◽  
High Performance Concrete ◽  
Chloride Ion ◽  
High Strength ◽  
Penetration Resistance ◽  
Pozzolanic Reaction ◽  
Mineral Admixture ◽  
Chemical Attack ◽  
Chloride Ion Penetration

Silica fume (SF) has become an environmental mineral admixture in the production of high-strength and high-performance concrete in modern concrete engineering. Through compacting all components and pozzolanic reaction, obvious mechanical enhancement of concrete is observed in the aspects of compressive strength tensile strength, elastic modulus as well as fracture toughness. Further more, durability improvement of silica fume concrete such as chloride-ion penetration resistance and chemical attack resistance are reported accordingly.

Study of Self-Compacting Fly Ash Concrete Using Silica Fume Admixture

2011 ◽  
Vol 409 ◽  
pp. 249-254
Author(s):  
Prakash Parasivamurthy ◽  
Veena Jawali ◽  
Pramod Aralumallige Venkatakrisna
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Silica Fume ◽  
Tap Water ◽  
Chloride Ion ◽  
High Volume ◽  
Ternary Blends ◽  
Self Compacting Concrete ◽  
High Rise ◽  
Chloride Ion Penetration

Concrete is the key material used in construction of various types, from flooring of a dwelling to multi-storied high rise structures, from pathways to an airport runways, from under ground tunnels and deep sea platforms to high-rise chimneys and towers. The greatest challenge in this millennium, especially in developing country like India, it needs to build concrete structures in quicker time, so as to meet high infrastructural demand. In order to achieve this, concrete construction practices will have to undergo a sea-change in the country. The study was focused on development of self-compacting concrete using high volume fly ash, admixed with quary dust and Silica fume. The objective of the study included evaluation of properties, viz. compressive strength, weight change observations in sulphate environment and resistance to chloride ion penetration. Several trial mixes were tested before optimizing the three Self-Compacting Concrete mixes based on binary and ternary blends. The strength variation of individual cubes in each of the mixes has been observed to be in the range of 28 to 46 MPa. Self-compacting concrete using high volume flyash, admixed with quary dust and Silica fume mixes have performed extremely well in aggressive chloride environments. Samples cured for 90 days and exposed to sulphate environment had reduced strengths compared to those cured in tap water, in all the blends. But the percentage reduction is lower in case of ternary blends as compared to control concrete. Keywords: Self-Compacting Concrete (SCC), Compressive Strength, High volume flyash, Quary dust, Silica fume, Supplementary Cementious Material (SCM).

scholarly journals Effects of Reinforcing Fiber and Microsilica on the Mechanical and Chloride Ion Penetration Properties of Latex-Modified Fiber-Reinforced Rapid-Set Cement Concrete for Pavement Repair

2018 ◽  
Vol 2018 ◽  
pp. 1-8
Author(s):  
Woong Kim ◽  
Jong-Chan Jeon ◽  
Byung-Hwan An ◽  
Joo-Ha Lee ◽  
Hae-Do Kim ◽  
...  
Keyword(s):  
Chloride Ion ◽  
Concrete Pavement ◽  
Target Strength ◽  
Fiber Reinforced ◽  
Cement Concrete ◽  
Emergency Repair ◽  
Chloride Ion Penetration ◽  
Reinforcement Fiber ◽  
Substitution Ratio ◽  
Ion Penetration

This study evaluated the influence of reinforcement fiber type and microsilica content on the performance of latex-modified fiber-reinforced roller-compacted rapid-hardening cement concrete (LMFRCRSC) for a concrete pavement emergency repair. Experimental variables were the microsilica substitution ratio (1, 2, 3, and 4%), and the reinforcement fiber (jute versus macrosynthetic fiber). In the tests, compressive, flexural, and splitting tensile strength; chloride ion penetration resistance; and abrasion resistance were assessed. From the compressive and flexural strength tests with microsilica substitution, the 4-hour curing strength decreased as the microsilica substitution ratio increased. From the chloride ion penetration test, as the microsilica substitution ratio increased, chloride ion penetration decreased. The abrasion resistances increased with the substitution ratio of microsilica increase. Based on these test results, microsilica at a substitution ratio of 3% or less and macrosynthetic fiber as the reinforcement improved the performance of LMFRCRSC for a concrete pavement emergency repair and satisfied all of the target strength requirements.

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