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

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).

2011 ◽  
Vol 250-253 ◽  
pp. 307-312 ◽  
Author(s):  
Muthuramalingam Jayakumar ◽  
M. Salman Abdullahi

Even though the use of fly ash in concrete is nowadays a common practice, its relatively slow pozzolanic reactivity hinders its greater utilization; hence efficient methods of activation are on demand. This study was carried out to evaluate the influence of lime as a chemical activator on the mechanical and durability properties of high strength fly ash concrete. Mixtures were made with 0, 30, 40, and 50% of cement replaced by low calcium fly ash. Corresponding mixtures were also made with the same amount of fly ash and addition of 10% of lime to each mixture. For each concrete mixture, slump, compressive strength, water absorption, sorptivity, apparent volume of permeable voids, and resistance to chloride-ion penetration were measured. The results obtained showed that addition of lime improved the compressive strength significantly at all ages. The strength of all the fly ash mixtures containing lime surpassed that of the corresponding Portland cement mix at 60 days. Addition of lime also improved the sorptivity and resistance to chloride-ion penetration of the fly ash concrete. It however increases the water absorption and the volume of permeable voids of the fly ash concrete.


2014 ◽  
Vol 64 ◽  
pp. 261-269 ◽  
Author(s):  
Watcharapong Wongkeo ◽  
Pailyn Thongsanitgarn ◽  
Athipong Ngamjarurojana ◽  
Arnon Chaipanich

2020 ◽  
Vol 184 ◽  
pp. 01109
Author(s):  
C Chandana Priya ◽  
M V Seshagiri Rao ◽  
V Srinivasa Reddy ◽  
S Shrihari

SCC is expensive when compared with normal conventional concrete. Hence, it is desired to produce low cost SCC by replacing cement with higher percentages of fly ash, which is a no cost material and available in abundance. At the same time to achieve higher grade HVFASCC, micro silica which is otherwise condensed silica fume can also be used along with fly ash to enhance the strength properties of HVFASCC. By replacing fly ash in high volumes in the mix, high amount of pozzolanic material becomes available, majorly reactive silica, for which more calcium hydroxide is necessary for further pozzolanic reaction. As we are reducing cement quantity, the amount of calcium hydroxide available is reduced thus demanding external addition of hydrated lime which can be supplied as additive to cater to the need of calcium hydroxide required for reactive silica in fly ash.The present investigation aims to achieve strength for high volume fly ash self-compacting concrete. The replacement of cement with fly ash is made in 45%, 50%, 55%, 60%, 65% and 70% with 20% hydrated lime and 10% silica fume in one trial. In another trial, 30% hydrated lime and 10% silica fume is added with replacement of fly ash to cement varying in same percentages. The design mix is tested for workability and flowability and cubes are casted for compression strength test and tested at 28 day,, 56 day, and 90 day,.


2021 ◽  
Vol 13 (10) ◽  
pp. 5571
Author(s):  
Wesam Salah Alaloul ◽  
Muhammad Ali Musarat ◽  
Sani Haruna ◽  
Kevin Law ◽  
Bassam A. Tayeh ◽  
...  

The existing form of self-compacting concrete (SCC) comprises of a large amount of powdered and fine materials. In this study, a part of the cementitious material was replaced with constant high-volume fly ash, and a portion of fine aggregates was substituted by crumb rubber (CR). Besides that, silica fume (SF) was added, with the hope that by implementing a new type of nanomaterial, the loss in mechanical strength due to previous modifications such as rubberization and replacement will be prevented. Two variables were found to influence the constituent/component in the mix design: SF and CR. The proportion of SF varies from 0% to 10%, while that of CR from 0% to 30% by volume of the total river sand, where 55% of cement was replaced by the fly ash. A total of 13 rubberized SCC samples with CR and SF as controlling variables were made, and their design mix was produced by a Design of Experiment (DOE) under the Response Surface Methodology (RSM). The results reveal a slight increase in the mechanical properties with the addition of SF. The theoretical mathematical models and equation for each different mechanical strength were also developed after incorporating the experimental results into the software.


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