scholarly journals Performance of Ternary Class F Pulverised Fuel Ash and Ground Granulated Blast Furnace Slag Concrete in Sulfate Solutions

Author(s):  
Ash Ahmed ◽  
John Kamau

Durability of concrete is defined as its ability to resist deterioration after it has been exposed to the environment of its intended use. This work examined the performance of combined (ternary) Pulverised Fuel Ash (PFA) and Ground Granulated Blast Furnace Slag (GGBS) concrete in sulfate solutions of sodium sulfate (Na2SO4), magnesium sulfate (MgSO4) and mixed Na2SO4 and MgSO4, as well as its performance in water absorption. Investigations were carried out on replacements that were found to have achieved the highest compressive strengths as well as on 30% replacements from a previous study. From the results obtained, it was also found that at highest compressive strengths, the ternary concrete could be used with an advantage over the individual binary concretes in MgSO4 environments, whereas at a higher replacement, the ternary concrete could be used with an advantage over individual binary specimens in Na2SO4 and MgSO4 environments. For visual observations, it was concluded that the ternary concrete could be used with an advantage over the individual binary concretes in Na2SO4 and MgSO4 environments, whereas for strength deterioration, the results showed that the ternary specimens could be used with an advantage over individual binary concretes in both the MgSO4 and the mixed sulfate solutions. Generally, the ternary specimens showed some complimentary effect from the two materials.

2015 ◽  
Vol 754-755 ◽  
pp. 359-363
Author(s):  
M. Azreen ◽  
M.W. Hussin

Ordinary Portland Cement (OPC) concrete is one of the most widely used construction materials globally, though its production in construction has negative environmental impact. About 0.9 ton of CO2is emitted for every one (1) ton of cement produced. In order to reduce the amount of CO2emission from cement industry, the utilization of supplementary cementitious materials such as pulverized fuel ash (PFA), blast-furnace slag and natural pozzolans is common and effective. Geopolymer is an inorganic binder material and can be produced by a geopolymeric reaction of alkali activating solution with silica and alumina rich source materials such as PFA and blast-furnace slag. In this study, the durability of concrete such as the resistance to sulfuric acid and sulfate solutions due to the effect of blended as of PFA and palm oil fuel ash (POFA), along with alkaline activators were investigated. Consequently, the optimum mix design of the blended ash geopolymer (BAG) concrete and OPC concrete specimens were prepared with water to cement ratio of 0.5 by mass as control. The micro structural analysis by X-ray diffraction (XRD) was done. BAG concrete showed better performance in 2% sulfuric acid and 5% sulfate solutions. From micro structural analysis, it was evident that BAG binder gel (N-A-SH) produced more durable material compared with C-S-H binder gel of OPC. The BAG concrete is strongly recommended to be used as an alternative to OPC concrete in addition to its environmental friendliness. Abundant PFA and POFA can be efficiently utilized to produce a high performance concrete.


Kilat ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 101-107
Author(s):  
Muhammad Sofyan

Mortar salah satu material yang memiliki manfaat yang beraneka ragam dalam konstruksi bangunan.  Sejauh ini, mortar konvensional digunakan sebagai bahan plester atau coating pada bangunan. Bahan pengikat utama mortar pada dasarnya masih mengandalkan semen. Pemanfaatan Batu bara pada pembangkit listrik tenaga uap masih menjadi salah satu arus utama sebagai pendukung kebutuhan energi listrik. Penumpukan hasil sisa pembakaran batu bara seperti fly ash dan bottom ash berpotensi mengganggu stabilitas Ekosistem lingkungan. Alkali-Activated mortar dengan mengandalkan larutan alkali activator yang direaksikan dengan material pozzolanic seperti fly ash, Ground Granulated Blast Furnace Slag (GGBFS), Palm Oil Fuel Ash (POFA)ldan lain-lain dapat menjadi salah satu solusi dalam mengurangi limbah fly-ash yang menumpuk. Dalam beberapa riset riset terdahulu idealnya kontrol mutu dari Alkali Activated mortar dapat ditinjiau pada kekuatan mekanisnya seperti kuat tekan dan lentur Dalam artikel ini akan ditinjau bagaimana kekuatan mekanis pada beberapa jenis Alkali-Activated Mortar. Dari studi-studi yang akan dibahas tersebut akan ditarik sebuah kesimpulan berdasarkan data-data pengujian mekanis yan pada akhirnya dapat memberi rekomendasi tentang bagaimana performa mekanis pada Alkali-Activated mortar.


2020 ◽  
Vol 39 (1) ◽  
pp. 97-104
Author(s):  
A.S. Bature ◽  
M. Khorami ◽  
A. Lawan

The rheology of concrete containing Pulverized Fuel Ash (PFA) and Ground Granulated Blast Furnace Slag (GGBS) has been scarcely studied and reported, despite their increase application as Supplementary Cementitious Materials (SCM) that drives improvement of sustainability of the construction industry. This work studied the effect of these SCMs and Superplasticizer proportions on rheological properties of concrete using rate controlled concrete rheometer. Two groups of mixes containing replacement or addition on mass basis using either PFA or GGBS or their combinations were derived from the control mix. The dynamic yield stress, plastic viscosity and 28 day compressive strength of the control mix are 1258 Pa, 6 PaS, and 40.5 MPa respectively. The results of the rheology tests of the various binary mixes (PFA and Portland cement) and ternary mixes (Portland cement, PFA and GGBS) structural concrete shows wide disparity in the measured rheological parameters. The results show that the decrease in dynamic yield stress of the ternary mix containing 20% GGBS is 4.1%, whereas the decrease in dynamic stress of the ternary mix containing 20% PFA is 35.9% compared to the control ternary mix. The high volume Portland cement replaced ternary concrete can therefore be effectively characterized as a workable and pumpable concrete. Keywords: Rheology, PFA, GGBS, superplasticizer, concrete.


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.


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