scholarly journals Strength and Microstructural Investigation of Quaternary Blended High-Strength Concrete

2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Ayele Bereda ◽  
Belachew Asteray
Keyword(s):  
Compressive Strength ◽  
Flexural Strength ◽  
High Strength Concrete ◽  
Setting Time ◽  
Ceramic Powder ◽  
High Strength ◽  
Supplementary Cementitious Materials ◽  
Partial Replacement ◽  
Microstructural Investigation ◽  
Strength Concrete

This research focuses on studying the effect of different supplementary cementitious materials (SCMs) such as waste ceramic powder (WCP), lime powder (LP), and ground granulated blast furnace slag (GGBS) in combination on strength characteristics and microstructure of quaternary blended high-strength concrete. To achieve the aims of the study, necessary physical and chemical composition tests were done for the raw materials. Then, mixes were designed into control mix with 100% Ordinary Portland Cement (OPC) and experimental mixes containing 30%, 40%, 50%, and 60% of GGBS, WCP, and LP in combination. Tests were conducted during casting and at curing ages of 7 and 28 days. Accordingly, the control mix which is concrete grade 50 (C-50) as per American Concrete Institute (ACI) mix design is used as a reference for comparison of test results with those specimens produced by partial replacement of SCMs. The characterizations of high-strength concrete are done using consistency, setting time, workability, compressive strength, flexural strength, and morphological tests. The optimum percentage replacement is 50% OPC replacement by 30% GGBS + 10% WCP + 10% LP. Based on the experimental investigations, the workability increases as the replacement level of SCMs increases from 30% to 60% by weight. Compressive strength and flexural strength results increase up to 11.41% and 20% when the percentage replacement increases from 30% to 50% of SCMs replacement at 28 days of curing time, respectively. There are also improvement in the microstructure and significant cost saving due to replacing OPC partially with SCMs with proportions mentioned above. Therefore, the practice of utilizing increased percentage of SCMs in quaternary blend in concrete can be beneficial for the construction industry and sustainability without compromising the quality of the concrete product.

Test Research on Strength of Concrete Shaft Lining under Salt Disaster Corrosion

2014 ◽  
Vol 926-930 ◽  
pp. 645-648 ◽  
Author(s):  
Xu Rong Li ◽  
Hong Guang Ji ◽  
Jun Wang ◽  
Cheng Lin Song
Keyword(s):  
Compressive Strength ◽  
Flexural Strength ◽  
High Strength Concrete ◽  
High Strength ◽  
Solution Concentration ◽  
Test Results ◽  
Strength Concrete ◽  
Strength Change ◽  
Lining Structure ◽  
Shaft Lining

In order to study the strength change of high strength concrete shaft lining structure in underground complex environment resisting composite salt damage erosion, C70 high strength concrete test specimens were made and composite salt disaster solutions of different concentrations were compounded. The test results show that the coefficient of compressive strength and flexural strength of high strength concrete increase in early corrosion and then decline. The strength of specimen declines more quickly in higher corrosion solution concentration in latter time. The change law of the flexural strength is more complex than the compressive strength. Composite salt disaster solutions have little effect for no damage high strength concrete.

scholarly journals Strength Determination of High Strength Concrete Blended with Copper Slag and Fly Ash

2021 ◽  
Vol 9 (VII) ◽  
pp. 1198-1203
Author(s):  
Jamshed Alam
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
High Strength Concrete ◽  
Free Water ◽  
High Strength ◽  
Copper Slag ◽  
Partial Replacement ◽  
Fine Aggregate ◽  
Strength Concrete ◽  
Free Water Content

An experimental analysis was conducted to study the effects of using copper slag as a fine aggregate (FA) and the effect of fly ash as partial replacement of cement on the properties high strength concrete. In this analysis total ten concrete mixtures were prepared, out of which five mixes containing different proportions of copper slag ranging from 0% (for the control mix) to 75% were prepared and remaining five mixes containing fly ash as partial replacement of cement ranging from 6% to 30% (all mixes contains 50% copper slag as sand replacements). Concrete matrix were tested for compressive strength, tensile strength and flexural strength tests. Addition of copper slag as sand replacement up to 50% yielded comparable strength with that of the control matrix. However, further additions of copper slag, caused reduction in strength due to an increment of the free water content in the mix. Concrete mix with 75% copper slag replacement gave the lowest compressive strength value of approximately 80 MPa at 28 days curing period, which is almost 4% more than the strength of the control mix. For this concrete containing 50% copper slag, fly ash is introduced in the concrete to achieve the better compressive, split and flexural strengths. It was also observed that, introduction of the fly ash gave better results than concrete containing 50% copper slag. When concrete prepared with 18 % of fly ash, the strength has increased approximately 4%, and strength decreased with further replacements of the cement with fly ash. Hence, it is suggested that 50% of copper slag can be used as replacement of sand and 18% fly ash can be used as replacement of cement in order to obtain high strength concrete.

scholarly journals Physical and Mechanical Properties of High-Strength Concrete Modified with Supplementary Cementitious Materials after Exposure to Elevated Temperature up to 1000 °C

Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 532 ◽  
Author(s):  
Jianwei Zhou ◽  
Dong Lu ◽  
Yuxuan Yang ◽  
Yue Gong ◽  
Xudong Ma ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Physical Properties ◽  
Water Absorption ◽  
High Strength Concrete ◽  
Elevated Temperatures ◽  
High Strength ◽  
Cementitious Materials ◽  
Supplementary Cementitious Materials ◽  
Strength Concrete

This paper presents the experimental findings of a study on the influence of combining usage of supplementary cementitious materials (SCMs) on the performance of high-strength concrete (HSC) subjected to elevated temperatures. In this study, four types of HSC formulations were prepared: HSC made from cement and fly ash (FA), HSC made from cement and ultra-fine fly ash (UFFA), HSC made from cement and UFFA-metakaolin (MK), and HSC made from cement and FA-UFFA-MK. Mechanical and physical properties of HSC subjected to high temperatures (400, 600, 800, and 1000 °C) were studied. Furthermore, the relation between residual compressive strength and physical properties (loss mass, water absorption, and porosity) of HSC was developed. Results showed that the combined usage of SCMs had limited influence on the early-age strength of HSC, while the 28-d strength had been significantly affected. At 1000 °C, the residual compressive strength retained 18.7 MPa and 23.9 MPa for concretes containing 30% UFFA-5% MK and 10% FA-20% UFFA-5% MK, respectively. The specimen containing FA-UFFA-MK showed the best physical properties when the temperature raised above 600 °C. Combined usage of SCMs (10% FA-20% UFFA-5% MK) showed the lowest mass loss (9.2%), water absorption (10.9%) and porosity (28.6%) at 1000 °C. There was a strongly correlated relation between residual strength and physical properties of HSC exposed to elevated temperatures.

The Formation of Microstructure in High Strength Concrete Containing Micro and Nanosilica

2014 ◽  
Vol 604 ◽  
pp. 83-86 ◽  
Author(s):  
Nikolajs Toropovs ◽  
Diana Bajare ◽  
Genadijs Sahmenko ◽  
Linda Krage ◽  
Aleksandrs Korjakins
Keyword(s):  
Compressive Strength ◽  
Calcium Hydroxide ◽  
Calcium Silicate ◽  
High Strength Concrete ◽  
High Strength ◽  
Microstructural Investigation ◽  
Strength Concrete ◽  
Calcium Silicate Hydrates ◽  
Nanosilica Particles ◽  
Aggregate Particles

This article presents the results of microstructural investigation of high strength concrete containing microsilica and nanosilica (amorphous SiO2) as an active pozzolanic admixture. Micro and nanosilica react with calcium hydroxide producing calcium silicate hydrates (C-S-H), thus the voids and pores within concrete are filled and new minerals are formed in the gaps between cement grains and aggregate particles. Unreacted round microsilica and nanosilica particles were registered using SEM even in 6 month old samples. The compressive strength results indicate that concrete still continues to harden after the 28-days of curing.

Mechanical Properties of Steel Fibre-Reinforced High Strength Concrete with High early-Age Strength Used in Freezing Shaft Lining

2012 ◽  
Vol 174-177 ◽  
pp. 1388-1393
Author(s):  
Hai Qing Song ◽  
Teng Long Zheng
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Flexural Strength ◽  
High Strength Concrete ◽  
Steel Fibre ◽  
High Strength ◽  
Plain Concrete ◽  
Split Tensile Strength ◽  
Strength Concrete

Plain concrete is susceptible to cracking under aggressive environment such as in freezing shaft. And addition of steel fibres in plain high strength concrete is proved to be effective in cracking resistance and brittleness improvement, etc. This paper presents results of experimental investigation carried out to study the mechanical properties of steel fibre-reinforced concrete having volume fractions of 0.38%, 0.51% and 0.64% for two types of fibres respectively. The results of this study revealed that there is an increase for all the mechanical properties such as compressive strength, split tensile strength, modulus of elasticity and flexural strength. Enhancement for split tensile strength and flexural strength is more evident than compressive strength.

scholarly journals Evaluation of Mix Proportions and Mechanical Properties of Normal and High-Strength Fibers Concrete

2019 ◽  
Vol 9 (2) ◽  
pp. 202-207
Author(s):  
Imad R. Mustafa ◽  
Omar Q. Aziz
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Flexural Strength ◽  
Silica Fume ◽  
High Strength Concrete ◽  
Steel Fiber ◽  
High Strength ◽  
Splitting Tensile Strength ◽  
Strength Concrete

An experimental program is carried out to evaluate the mix design and mechanical properties of normal strength concrete (NSC) grade 40 MPa and high-strength concrete grade 60 and 80 MPa. The study investigates using silica fume to produce high-strength concrete grade 80 MPa and highlights the influence of adding steel fiber on the mechanical properties of normal and high-strength concrete. For NSC, the compressive strength is found at 7 and 28 days. While for higher strength concrete, the compressive strength is determined at 7, 28, and 56 days. The splitting tensile strength and flexural strength is determined at 28 days. Based on results, the specimens with 14% silica fume are higher compressive strength than the specimens with 10% silica fume by 21.8%. The presence of steel fiber increased the compressive strength of normal and high-strength concrete at 7, 28, and 56 days curing ages with different percentage and the steel fiber has an important role in increasing the splitting tensile strength and flexural strength of normal and high-strength concrete.

Effects of Nano-CaCO3 on the Compressive Strength and Microstructure of High Strength Concrete in Different Curing Temperature

2011 ◽  
Vol 121-126 ◽  
pp. 126-131 ◽  
Author(s):  
Qing Lei Xu ◽  
Tao Meng ◽  
Miao Zhou Huang
Keyword(s):  
Compressive Strength ◽  
Low Temperature ◽  
High Strength Concrete ◽  
High Strength ◽  
Curing Temperature ◽  
Test Results ◽  
Strength Concrete ◽  
Calcium Nitrite ◽  
Orientation Index ◽  
Early Strength

In this paper, effects of nano-CaCO3 on compressive strength and Microstructure of high strength concrete in standard curing temperature(21±1°C) and low curing temperature(6.5±1°C) was studied. In order to improve the early strength of the concrete in low temperature, the early strength agent calcium nitrite was added into. Test results indicated that 0.5% dosage of nano-CaCO3 could inhibit the effect of calcium nitrite as early strength agent, but 1% and 2% dosage of nano-CaCO3 could improve the strength of the concrete by 13% and 18% in standard curing temperature and by 17% and 14% in low curing temperature at the age of 3days. According to the XRD spectrum, with the dosage up to 1% to 2%, nano-CaCO3 can change the orientation index significantly, leading to the improvement of strength of concrete both in standard curing temperature and low curing temperature.

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