Effect of Aggregate Max Size on the Rheological Properties of Self Consolidating Concrete

2020 ◽  
Vol 853 ◽  
pp. 193-197
Author(s):  
Samer Al Martini ◽  
Ziad Hassan ◽  
Ahmad Khartabil

The effects of aggregate size and supplementary cementitious materials (SCMs) on the rheology of self-consolidating concrete (SCC) were studied in this paper. Two main concrete mixtures with different maximum aggregate sizes were prepared and investigated. The first mix had a maximum size aggregate of 5 mm and the second mix was with 20 mm max size aggregates. All mixes incorporated different dosages of Ground granulated blast furnace slag (GGBS). The rheology of all mixes investigated was measured over 2 hour time period. It was found that the size of aggregates and GGBS dosage have influence on the yield stress of studied concrete mixes.

Energies ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 5190
Author(s):  
Laura Boquera ◽  
David Pons ◽  
Ana Inés Fernández ◽  
Luisa F. Cabeza

Six supplementary cementitious materials (SCMs) were identified to be incorporated in concrete exposed to high-temperature cycling conditions within the thermal energy storage literature. The selected SCMs are bauxite, chamotte, ground granulated blast furnace slag, iron silicate, silica fume, and steel slag. A microstructural characterization was carried out through an optical microscope, X-ray diffraction analysis, and FT-IR. Also, a pozzolanic test was performed to study the reaction of SCMs silico-aluminous components. The formation of calcium silica hydrate was observed in all SCMs pozzolanic test. Steel slag, iron silicate, and ground granulated blast furnace slag required further milling to enhance cement reaction. Moreover, the tensile strength of three fibers (polypropylene, steel, and glass fibers) was tested after exposure to an alkalinity environment at ambient temperature during one and three months. Results show an alkaline environment entails a tensile strength decrease in polypropylene and steel fibers, leading to corrosion in the later ones.


2020 ◽  
Vol 16 (3) ◽  
pp. 185
Author(s):  
Rizki Amalia Tri Cahyani ◽  
Ernawan Setyono ◽  
Yunan Rusdianto

Serangan sulfat (sulfate attack) termasuk hal yang umum terjadi pada struktur beton, mengingat ion sulfat banyak dijumpai pada tanah, air tanah dan air laut. Peningkatan ketahanan beton melawan sulfat akan berdampak besar pada durabilitas dan umur layan struktur beton. Penambahan supplementary cementitious materials seperti GGBFS (ground granulated blast furnace slag) ke campuran beton telah terbukti memberikan pengaruh positif terhadap durabilitas dan properti mekanis beton. Namun, GGBFS tergolong material yang baru dikembangkan di Indonesia dan potensinya dalam meningkatkan durabilitas beton belum dimanfaatkan secara luas. Berdasarkan hal tersebut, perlu dilakukan investigasi terkait aplikasi GGBFS dan pengaruhnya terhadap durabilitas beton, terutama dalam melawan serangan sulfat. Dalam studi ini, durabilitas beton dengan persentase penggantian GGBFS 30%, 50% dan 70% terhadap total volume binder dievaluasi menggunakan perlakuan siklus basah-kering dalam larutan magnesium sulfat. Tingkat degradasi beton diukur dengan melakukan observasi terhadap perubahan kuat tekan dan massa spesimen akibat serangan sulfat. Hasil penelitian menunjukkan bahwa penggantian GGBFS hingga 50% dari total volume binder dapat meningkatkan ketahanan beton terhadap serangan sulfat, ditunjukkan dengan kehilangan massa dan reduksi kekuatan yang lebih rendah dibandingkan spesimen kontrol dengan 100% semen Portland.


2021 ◽  
Vol 17 ◽  
pp. 271-281
Author(s):  
Efstratios Badogiannis ◽  
Eirhnh Makrinou ◽  
Marianna Fount

A study on the durability parameters of normal and lightweight aggregate mortars, incorporated different supplementary cementitious materials (SCM) is presented. Mortars were prepared using limestone or pumice as aggregates and Metakaolin, Fly ash, Granulated Blast Furnace Slag and Silica Fume, as SCM, that they replaced cement, at 10 % by mass. Ten different mortars, having same water to binder ratio and aggregate to cement volumetric ratio, they were compared mainly in terms of durability. The use of pumice sand was proved to be effective not only to the density of the mortars as it was expected, but also in durability, fulfilling at the same time minimum strength requirements. The addition of the different SCM further enhanced the durability of the mortars, where Metakaolin was found to be the most effective one, especially against chloride’s ingress.


2019 ◽  
Vol 803 ◽  
pp. 233-238 ◽  
Author(s):  
Samer Al Martini ◽  
Ziad Hassan ◽  
Ahmad Khartabil

The paper investigates the effects of aggregate size and supplementary cementitious materials (SCMs) on flow behavior of self-consolidating concrete (SCC). The fresh performance of concrete mixes was evaluated through slump flow and V funnel tests. Some concrete mixes were prepared with 5 mm maximum size aggregates and other mixes with 20 mm maximum size aggregates. The effects of varying contents of SCMs (Fly ash F and GGBS) on flow behavior of SCC under binary blends were also studied. The results show that the maximum size of aggregates has effect on the flow behavior of SCC.


2017 ◽  
Vol 2 (6) ◽  
pp. 36
Author(s):  
Jhon Kamau ◽  
Ash Ahmed ◽  
Paul Hirst ◽  
Joseph Kangwa

Cement is the most utilised material after water, and the processes that are involved in making it are energy intensive, contributing to about 7% of the total global anthropogenic carbon dioxide (CO2). Energy efficiency can however be achieved by using Supplementary Cementitious Materials (SCMs) such as Pulverised Fuel Ash (PFA) and Ground Granulated Blast Furnace Slag (GGBS) which demand less process heating and emit fewer levels of CO2. This work examined the advantages of substituting cement using PFA and GGBS in ternary (2 SCMs) concrete at steps of 0%, 5%, 7.5%, 10%, 15%, 20%, 25%, and 30%. It was found that PFA increased the workability of GGBS, whereas GGBS improved the strength of PFA. The densities of the resultant concrete were below those of the 0% replacement as well as those of individual binary (1 SCM) concretes. The tensile strengths of the ternary concrete were lower than those of the binary concretes, whereas the gains in compressive strengths over curing time were higher at lower replacements for the ternary concrete compared with the 0% replacement and the binary concretes, but lower at higher replacements. The findings indicate that PFA and GGBS could be used together to improve the properties of concrete where each falls short.


2021 ◽  
Vol 28 (3) ◽  
pp. 111-115
Author(s):  
Ameer Baiee ◽  

For sustainability purposes, supplementary cementitious materials (SCMs) are considered essential components for gaining ultra-high strength properties of concrete and mortar. This study experimentally investigates the influence of single, binary, and ternary partial cement replacements of the SCMs on the performance of ultra-high-strength mortar. The investigated SCMs were included ground granulated blast furnace slag (GGBS), densified silica fume (DSF), un-densified silica fume (UDSF), and Fly ash (FA). Three replacements ratios were implemented; 10%, 20%, and 30% in addition to mortar without SCMs to work as a control mix for comparison reasons. 27 mixes were designed to quantify the replacement ratio that explains the best performance, through examining the workability, compressive and tensile strength of each mix. In addition, XRD test was carried out to identify the various decomposition phases of the hardened mortar. The results indicated that binary replacement of 15% GGBS and 15% UDSF exhibited the best performance among all other replacements ratios.


2017 ◽  
Vol 744 ◽  
pp. 136-140 ◽  
Author(s):  
Osama Ahmed Mohamed ◽  
Modafar Ati ◽  
Omar Fawwaz Najm

The adverse environmental impact of the construction industry may be mitigated through the partial replacement of cement with supplementary cementitious materials (SCM). SCMs such as ground granulated blast furnace slag (GGBS), impart many favourable fresh and long-term concrete properties. A study by Mohamed [1] assessed the splitting tensile strength of sustainable self- consolidating concrete in which up to 80% of the cement was partially replaced with ground granulated blast furnace slag (GGBS), and developed a prediction formula for the splitting tensile strength. In this paper, the tensile strength prediction formula developed by Mohamed et al. [1] is benchmarked against formulas proposed in different building codes and validated with additional test results obtained from the literature. The proposed prediction formula showed excellent correlation to experimental data obtained from the literature.


Materials ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1798
Author(s):  
Yanfei Yue ◽  
Jing Jing Wang ◽  
P. A. Muhammed Basheer ◽  
Yun Bai

Establishing the carbonation profile is of great significance to the prediction of the service life of reinforced concrete structures. In our previous work, Raman spectroscopy was shown to be an efficient tool for characterizing calcium carbonate (CaCO3) polymorphs and their profile in plain Portland cement (PC) matrices. However, as supplementary cementitious materials (SCMs), particularly fly ash (FA) and ground granulated blast furnace slag (GGBS), are widely used in concrete, establishing the carbonation profile without considering the possible effects of these SCMs could be of little significance to the real world. This paper, thus, investigated the effects of FA and GGBS on the working capacity and reliability of Raman spectroscopy for establishing the carbonation profile in PC blends containing SCMs. The thermogravimetry (TG) analysis was also conducted to verify the results from Raman spectroscopy. The results show that Raman spectroscopy demonstrated a good capacity for differentiating the variation of CaCO3 contents in FA or GGBS blends. However, the incorporation of FA and GGBS into the PC system caused some adverse effects on the quantification of CaCO3 by Raman spectroscopy, which could be attributed to the darker color and weak scatter nature of FA and the high content of glassy phases in GGBS.


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