Effect of class F fly ash on the durability properties of concrete

Class F fly ash contains a small quantity of lime Thus compressive strength is reduced with the increment of fly ash content in concrete However due to the pozzolanic activity of fly ash the compressive strength increased in later stages of curing [4] [5] The amorphous silica present in fly ash undergoes a chemical reaction with the calcium hydroxide and

Prediction of setting time of fly ash concrete ResearchGate

A model for predicting the initial setting time of concrete with and without fly ash is presented Based on a theoretical initial spacing between the particles of unhydrated cementitious material

Modified Time of Setting Test for Fly Ash Paste and Fly

penetrometer to test the strength gain versus the time of setting Additionally the fly ash soil mixture has a time of setting that is slightly different from that of fly ash itself The time of setting of fly ash soil mixtures directly relates to the compaction delay Misra 1998; Mackiewicz and Ferguson 2005; Senol et al 2006

Effect on Compressive Strength of Concrete by Partial Replacement

In the present study replacement of fly ash with cement have been studied for partial replacement of fly ash with cement at 10% 20% 30% It was observed that 10% replacement of fly ash was 20%

Fresh Setting and Hardened Properties of Fly Ash Concrete

Nano silica NS may counteract the drawbacks of fly ash FA such as delayed setting and low early strength by accelerating hydration and providing higher early strength in concrete In this study concrete mixtures having 4 different FA replacement ratios 0% 20% 35% and 50% by vol and 3 different NS dosages 0% % and % by vol were

Use of Fly Ash and Slag in Concrete A Best

In fresh concrete fly ash reduces water demand in concrete increases workability and pump ability bleeding and doesn t affect setting time In hardened concrete in the later stages it increases the compression strength compared to OPC while the long term shrinkage and creep is similar or lower than OPC concrete of same grade

Optimizing the Use of Fly Ash in Concrete

In the present study two pozzolanic materials are used Metakaolin MK and Fly Ash PFA as binary and ternary partial replacement binders with Portland cement PC to investigate their effect

Setting Time Strength and Bond of High Calcium Fly Ash

In this paper setting time strength and bond of high calcium fly ash geopolymer concrete were investigated The high calcium fly ash was from Mae Moh power plant in northern Thailand

Investigation on the Compressive Strength and Time of Setting

Setting Time Determining the initial and final setting time of both cement and geopolymer is necessary for in situ applications The length of time from the moment where the cement makes contact with water to the time where it turns into a paste and begins to lose its plasticity is referred to as its initial setting time [] It should not be so fast that it becomes

Review Research progress on the setting time and

They proved that the setting time was the longest about 70 min when the M/P ratio was 2 and the aggregate to cement ratio was and that the setting time was about 65 min under the other conditions The mass ratio of coarse and fine aggregate had no significant effects on the setting time of the concrete

Designing Concrete with Fly ash Indian Cement Review

Cement companies should treat a blend of OPC and virgin fly ash as a benchmark in terms of workability cost strength etc when setting performance targets for the production of PPC The usage of PPC or a blend of OPC and fly ash has become the pressing need of today to maintain sustainability in construction […]

Setting Times of Fly Ash and Slag Cement Concretes as Affected

The results show that as the temperature increases the initial and final setting times decrease for all types of concrete with fly ash concrete having the longest setting times

The Effect of Blast Furnace Slag/Fly Ash Ratio on Setting

The effects of FA on the initial and final setting time were more pronounced for mixes containing a lower dose 5 wt % of the alkali activator Figures 2A the case of the mix containing 60 wt % FA and activated with 5 wt % SS at M s = 1 the delay of the initial setting time was nearly 850 min compared to 300 min at 20 wt % FA This is related to the significantly

Review of the Effects of Supplementary Cementitious Materials

Both types of fly ash were found to increase the setting time of concrete [20 30]; however the setting time is influenced by the characteristics and amount of fly ash used in the concrete [26 31] The strength of fly ash concrete depends on the type of cement used quality of

Fly ash for sustainable construction A review of fly ash concrete

The hydration products formed in these types of mixtures are based on lime or cement with or without mineral addition filling the pores and at the same time densifying the granular skeleton

PDF Anticipating the Setting Time of High Volume Fly Ash Concrete

One common concern limiting the proliferation of high volume fly ash HVFA concrete mixtures is the significant delay in setting that is sometimes encountered in field concrete mixtures

Consistency of fly ash quality for making high volume fly ash concrete

Fly ash is a by product of coal burning and is widely used as a substitute for cement material The advantages of using fly ash in concrete include the improvement of workability and reduction of

Fly ash GCCA

As a result fly ash concrete is likely be more durable over time an important benefit in terms of the economic social and environmental sustainability of the buildings it is used to construct In addition the spherical nature of fly ash particles improves the workability of concrete reducing the amount of water needed during production

Rheology Setting Time and Compressive Strength of Class F Fly Ash

AbstractThis paper investigates the incorporation of ordinary portland cement OPC to adjust/improve the workability setting time and compressive strength of Class F fly ash FA based geopolymer binder The geopolymer binder specimens were produced by

Fly ash based geopolymer clean production properties and applications

The setting time of fly ash based geopolymer is usually considered for the workability of final fly ash based geopolymer products In general the final setting can be achieved within 1 2 h at room temperature while Class C fly ash with high CaO content and calcium content additives such as CaCl 2 were found to shorten the setting time of

Best Practices Guide for High Volume Fly Ash Concretes

estimated at 15 % of the total cementitious binder portland cement fly ash and slag in ready mixed concrete in the with the usage consistently trending upwards during the past ten years With much fly ash still being diverted to landfills and existing landfills filled with fly ash

PDF Experimental Study on Use of Fly Ash in Concrete

To study the use of fly ash in concrete cement is replaced partially by fly ash in concrete In this experimental work concrete mix prepared with replacement of fly ash by 0% 25% 50% 75% and 100%