Permeability of Concrete Containing Air-Entraining and Mineral Admixtures

2011 ◽  
Vol 250-253 ◽  
pp. 425-429
Author(s):  
Wei Rong Huang ◽  
De Bin Yang ◽  
Jian Ting Zhou ◽  
Li Li ◽  
Wei Na Zhang
Keyword(s):  
Mechanical Properties ◽  
Fly Ash ◽  
Chloride Ion ◽  
Mineral Admixtures ◽  
Cement Ratio ◽  
Air Content ◽  
Chloride Ion Penetration ◽  
Saline Area ◽  
Electric Flux ◽  
Better Than

In this paper, the performance of concrete is studied through different water-cement ratio, different air-content, different mineral admixtures, different admixture contents, examined the mechanical properties of concrete, electric flux and chloride ion penetration depth of different mix concrete. The results show that, decreasing w/c ratio, proper air content, adding mineral admixtures can improve the resistance of chloride-permeation. Within some contents, the chloride-permeation resistance using silicides is better than that of fly-ash or slag. On this basis, the proper scheme of mix ratio used in saline area is recommended: the air-content is 3%～5%, the content of fly-ash or slag is 20%～30%, the content of silicides is 6%～8%, and double mixed with silicides.

scholarly journals The Influence of Crystalline Admixtures on the Properties and Microstructure of Mortar Containing By-Products

Buildings ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 146
Author(s):  
Jakub Hodul ◽  
Nikol Žižková ◽  
Ruben Paul Borg
Keyword(s):  
Mechanical Properties ◽  
Fly Ash ◽  
Chloride Ion ◽  
Capillary Suction ◽  
Chloride Ion Penetration ◽  
Chloride Migration ◽  
Cement Mortars ◽  
Polymer Mortar ◽  
By Products ◽  
Ion Penetration

Crystalline admixtures and industrial by-products can be used in cement-based materials in order to improve their mechanical properties. The research examined long-term curing and the exposure to environmental actions of polymer–cement mortars with crystalline admixture (CA) and different by-products, including Bengħisa fly ash and Globigerina limestone waste filler. The by-products were introduced as a percentage replacement of the cement. A crystallization additive was also added to the mixtures in order to monitor the improvement in durability properties. The mechanical properties of the mortar were assessed, with 20% replacement of cement with fly ash resulting in the highest compressive strength after 540 days. The performance was analyzed with respect to various properties including permeable porosity, capillary suction, rapid chloride ion penetration and chloride migration coefficient. It was noted that the addition of fly ash and crystalline admixture significantly reduced the chloride ion penetration into the structure of the polymer cement mortar, resulting in improved durability. A microstructure investigation was conducted on the samples through Scanning Electron Microscopy-Energy Dispersive X-ray Spectroscopy (SEM-EDS). Crystals forming through the crystalline admixture in the porous structure of the material were clearly observed, contributing to the improved properties of the cement-based polymer mortar.

Effect of Metakaolin-Based Modifier on the Permeability of Concrete Structure in the Marine Environment

2013 ◽  
Vol 438-439 ◽  
pp. 117-120
Author(s):  
Jun Tao Ma ◽  
Liang Yan ◽  
Yu Ping Tong ◽  
Hui Xian Wang
Keyword(s):  
Fly Ash ◽  
Marine Environment ◽  
Concrete Structure ◽  
Chloride Ion ◽  
Penetration Resistance ◽  
Chloride Ion Penetration ◽  
Working Performance ◽  
Electric Flux ◽  
Penetration Behavior ◽  
Strength And Durability

Corrosion of the steel reinforcement in the concrete structure caused by chloride ion penetration becomes more serious in the marine environment. Metakaolin has been widely used in the concrete structure to improve the strength and durability. The combination of metakaolin (MK) and fine fly ash (FA) was studied in the article and the penetration behavior of concrete with various contents of metakaolin-based modifier is investigated. The penetration resistance of concrete was tested in combination of electric flux test. The improving mechanism was studied with mercury intrusion porosimetry analysis (MIP). The experiment results indicate that metakaolin-based modifier improved the penetration resistance of concrete obviously. The combination of fine fly ash weakened the water sucking action of metakaolin and preserved the working performance of concrete. The pore size distribution of concrete containing metakaolin-based modifier has been optimized to improve the microstructure and enhance the penetration resistance of concrete.

Production and engineering application of C60 high-performance pump pebble concrete containing ultra-fine fly ash

2008 ◽  
Vol 35 (8) ◽  
pp. 757-763 ◽  
Author(s):  
Ying Li Gao ◽  
Bao Guo Ma ◽  
Shi Qiong Zhou
Keyword(s):  
Fly Ash ◽  
High Performance ◽  
Engineering Application ◽  
Chloride Ion ◽  
Test Method ◽  
Ordinary Concrete ◽  
Second Stage ◽  
Chloride Ion Penetration ◽  
Engineering Requirement ◽  
Better Than

C60 grade high-performance pump concrete incorporating river pebbles and ultra-fine fly ash (UFA) was successfully prepared, with UFA replacing 30% of the cement, for the second-stage of construction of the Hunan Xiangtan Power Plant. Some of the properties of this pump concrete were studied using both laboratory and on-site testing. The results indicated that workability of UFA concrete was excellent. The initial slump surpassed 180 mm, and the slump loss was small. The 28 d strength of the concrete met the engineering requirement of conforming to C60 strength grade. It is shown that the resistance–chloride ion penetration of UFA pump concrete is better than that of ordinary concrete in terms of Association for Testing and Materials test method C1202-94. Dry shrinkage of concrete slightly reduced with the addition of UFA, and UFA concrete shows better crack resistance compared with ordinary concrete. The production technology of UFA pump pebble concrete is summarized based on test and engineering applications.

scholarly journals Effect of Assembly Unit of Expansive Agents on the Mechanical Performance and Durability of Cement-Based Materials

Coatings ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 731
Author(s):  
Lin Wang ◽  
Chunxue Shu ◽  
Tiantian Jiao ◽  
Yong Han ◽  
Hui Wang
Keyword(s):  
Blast Furnace ◽  
Fly Ash ◽  
Blast Furnace Slag ◽  
Chloride Ion ◽  
Penetration Resistance ◽  
Mineral Admixtures ◽  
Expansion Rate ◽  
Chloride Ion Penetration ◽  
Assembly Unit ◽  
Furnace Slag

This paper studies the influence of assembly unit of expansive agents (CaO and calcium sulphoaluminate) on the limited and free compressive strengths, the limited expansion rate, carbonation resistance, chloride ion penetration resistance and corrosion resistance of reinforcement concrete. The dosages of expansive agent were 0%, 3%, 6%, 9%, and 12% by the total amount of cementitious materials. Two kinds of mineral admixture (blast furnace slag and fly ash) were applied in this study. Results show that suitable dosage (lower than or equal to 9%) of double expansion agent with a large amount of mineral admixtures can improve the limited and free compressive strengths. However, when the dosage of the double expansion agent is higher than 9%, the addition of the double expansion agent leads to the reduction of limited and free compressive strengths. The variation of the limit expansion rate reaches the maximum value when the curing age is 14 days. The increasing addition of expansive agents and lower water-binder ratio demonstrate positive effect on the limited expansion rate. Concrete with 60% mineral admixtures (fly ash and ground granulated blast furnace slag) shows lower limited expansion rate and higher compressive strength than the concrete with 50% mineral admixtures. Finally, the incorporation of double expansion agent can improve the resistance to carbonation, chloride ion penetration resistance, anti-corrosion of steel bars and mechanical strengths (the limited and free compressive strengths).

Ultra-Low Cement Dosage Hill Sand Concrete’s Electric Flux and Carbonization Performance Study

2014 ◽  
Vol 584-586 ◽  
pp. 1332-1336
Author(s):  
Wei Wei Hu ◽  
Li Bin Xu ◽  
Yi Dong ◽  
Xiao Peng Nie
Keyword(s):  
Materials Science ◽  
Chloride Ion ◽  
Social Stability ◽  
Concrete Durability ◽  
Test Results ◽  
Performance Study ◽  
Chloride Ion Penetration ◽  
Concrete Materials ◽  
Electric Flux ◽  
Low Dosage

Concrete durability is closely related to the national economy and social stability, environmental protection, sustainable development is a major research topic concrete materials science, engineering and technological problems are a major concern. This paper studies resistance to chloride Ion penetration performance and anti-carbonation of low cement concrete sand hill. And combined with the test results analysis and discussion the low dosage of cement to sand concrete electric flux and the influence of carbonization resistance.

scholarly journals Effect of Mineral Admixtures on Mechanical Properties of Concrete with Partially Replacement of Flyash and Ggbs

2018 ◽  
Vol 7 (3.35) ◽  
pp. 43
Author(s):  
Pothunuri Shalini kumari ◽  
K. Srinivas Rao ◽  
Tirumala Deepika
Keyword(s):  
Mechanical Properties ◽  
Fly Ash ◽  
Adverse Effects ◽  
Manufacturing Process ◽  
Binder Content ◽  
Mineral Admixtures ◽  
Huge Amount ◽  
Content Ratio ◽  
Tremendous Amount

Being humans the usage of concrete is more and more important now a days. Generally many people have dreams to construct their own houses and also government is take up many big projects like construction of dams, bridges etc. This shows us the necessity of production of huge amount of concrete. But for the production of concrete tremendous amount of cement is required, which in turn leads to the release of large amounts of CO2 into the atmosphere during its manufacturing process. It causes adverse effects to the environment. To decrease amount of CO2 and its adverse effects, we partially replaced the cement with mineral admixtures like GGBS and Fly ash. The present study dealt with the mechanical properties of concrete by using various percentages of mineral admixtures with water to binder content ratio 0.4 and M40 grade of concrete.  

scholarly journals Characterizing the Performance of Ternary Concrete Mixtures Involving Slag and Metakaolin

2020 ◽  
Vol 5 (2) ◽  
pp. 14
Author(s):  
Matthew S. Sullivan ◽  
Mi G. Chorzepa ◽  
Stephan A. Durham
Keyword(s):  
Mechanical Properties ◽  
Thermal Expansion ◽  
Fly Ash ◽  
Coefficient Of Thermal Expansion ◽  
Drying Shrinkage ◽  
Chloride Ion ◽  
Cementitious Materials ◽  
Ternary Mixtures ◽  
Modulus Of Rupture ◽  
Ternary Blends

Ternary blends of cementitious materials are investigated. A cement replacement level of 45% is used for all ternary mixtures consisting of 15% metakaolin and 30% slag replacements. Three metakaolin and two blast furnace slag, referred to as ‘slag’ for short, products commercially available are used to compare performance in ternary blends. A mixture with a 45% fly ash replacement is included to serve as a benchmark for performance. The control mixture contains 422 kg of cement per cubic meter of concrete, and a water-to-cementitious material ratio of 0.43 is used for all mixtures with varying dosages of superplasticizer to retain workability. Mixtures are tested for mechanical properties, durability, and volumetric stability. Mechanical properties include compression, split-cylinder tension, modulus of rupture, and dynamic Young’s modulus. Durability measures are comprised of rapid chloride-ion penetrability, sulfate resistance, and alkali–silica reactivity. Finally, the measure of dimensional stability is assessed by conducting drying shrinkage and coefficient of thermal expansion tests. Results indicate that ternary mixtures including metakaolin perform similarly to the control with respect to mechanical strength. It is concluded that ternary blends perform significantly better than both control and fly ash benchmark in tests measuring durability. Furthermore, shrinkage is reduced while the coefficients of thermal expansion are slightly higher than control and the benchmark.

scholarly journals Influence of Fly Ash Additive on the Properties of Concrete with Slag Cement

Materials ◽  
2020 ◽  
Vol 13 (15) ◽  
pp. 3265 ◽  
Author(s):  
Anna Szcześniak ◽  
Jacek Zychowicz ◽  
Adam Stolarski
Keyword(s):  
Fly Ash ◽  
Chloride Ion ◽  
High Strength ◽  
Experimental Tests ◽  
Chloride Ions ◽  
Strength Increase ◽  
Slag Cement ◽  
Initial Strength ◽  
Chloride Ion Penetration ◽  
The Impact

This paper presents research on the impact of fly ash addition on selected physical and mechanical parameters of concrete made with slag cement. Experimental tests were carried out to measure the migration of chloride ions in concrete, the tightness of concrete exposed to water under pressure, and the compressive strength and tensile strength of concrete during splitting. Six series of concrete mixes made with CEM IIIA 42.5 and 32.5 cement were tested. The base concrete mix was modified by adding fly ash as a partial cement substitute in the amounts of 25% and 33%. A comparative analysis of the obtained results indicates a significant improvement in tightness, especially in concrete based on CEM IIIA 32.5 cement and resistance to chloride ion penetration for the concretes containing fly ash additive. In the concretes containing fly ash additive, a slower rate of initial strength increase and high strength over a long period of maturation are shown. In accordance with the presented research results, it is suggested that changes to the European standardization system be considered, to allow the use of fly ash additive in concrete made with CEM IIIA 42.5 or 32.5 cement classes. Such a solution is not currently acceptable in standards in some European Countries.

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