dormant period concrete

dormant period concrete

Cement Chemistry The Concrete Portal

2019. 11. 1.  This is termed as the ‘dormant’ or the ‘induction’ period. This period is followed by the main peak of cement hydration, which is associated with the rapid dissolution of C 3 S to form CSH and CH, and formation of ettringite (AF t) from C 3 A.

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The dormant period of cement hydration

In the aim of interest is the early stage of reaction, after the initial mixing and the first reaction climax and before the concrete starts to harden. This period is so called the dormant period. For the building practice this period plays an important roll, because it controls

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Hydration of Cement Heat of Hydration Stages of

2019. 7. 14.  This is called as the Dormant Period. The existence of the dormant period allows the concrete to be transported to the construction site and placed and finished in the forms. Stage 3 Hydration Acceleration: The end of the dormant period shows the beginning of the setting at which time the cement

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Monitoring Concrete Temperature in Extreme Weather

2018. 3. 23.  During this period fresh concrete is transported and placed. At this time, the concrete has not yet hardened and is still workable (plastic and fluid). The length of the dormant period has been shown to vary depending on multiple factors (cement type, admixtures, w/cm, etc.). The end of the dormant period is typically characterized by the initial set.

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Concrete: Glossary

2000. 3. 1.  Dormancy period: Time period that concrete retains it workability. Elasticity: The ability of a material to return to its original shape after being stretched. Forms: Holders in which concrete is placed to harden. Gypsum: Calcium sulfate dihydrate, CaSO4.2H2O added to cement to regulate setting.

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Study of aggregate dormancy and its effects on the properties of

2020. 12. 12.  concrete work were usually abandoned on site for some times with minimum of 6 month or more due to different factors as it may apply. Some which might be due to lack of fund by the client and tussles. This abandonment led to a situation where construction materials are piled onsite over a range of periods

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Concrete: Quizes

2000. 3. 1.  The dormancy period of fresh concrete is the period during which the concrete is in a plastic state and the reaction is very, very slow. This state lasts from 1 to 3 hours and allows contractors to transport concrete to the job site and consolidate it before it hardens.

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Retarders for Concrete Mechanism, Types and Effects on

Mechanisms of Retardation. Adding a retarder, dissolved in the mixing water or sprayed on the surface of the concrete, temporarily interrupts the hydration reactions, which creates a longer dormant period. The mechanisms that appear depend on the combination of the type of retarder and the type of cement.

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Monitoring Concrete Temperature in Extreme Weather

2018. 3. 23.  During this period fresh concrete is transported and placed. At this time, the concrete has not yet hardened and is still workable (plastic and fluid). The length of the dormant period has been shown to vary depending on multiple factors (cement type, admixtures, w/cm, etc.). The end of the dormant period

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CIVL 1101 Part 4 Hydration of Portland Cement

2021. 1. 22.  Stage 2 Dormant period causes cement to remain plastic (2-4 hours). The reaction slows. CH crystallizes from the solution, C-S-H develops on the surface of the C 3 S and forms a coating.

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Properties and effects of dormant aggregates on concrete

Aggregates used for concrete are sometimes abandoned on sites for extended periods of time. These aggregates are left dormant and exposed to harsh weather conditions before utilization. This study investigates the effect of aggregate dormancy of both fine aggregate (river sand) and coarse aggregate (gravel) on quality of concrete produced and its strength.

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Properties and effects of dormant aggregates on concrete

2019. 11. 1.  Aggregates used for concrete are sometimes abandoned on sites for extended periods of time. These aggregates are left dormant and exposed to harsh weather conditions before utilization. This study investigates the effect of aggregate dormancy of both fine aggregate (river sand) and coarse aggregate (gravel) on quality of concrete produced and its strength.

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Hydration Of Cement Expert Civil Engineering Blog

As the dormant period progresses, the paste becomes too stiff to be workable. At the end of the dormant period, the alite and belite in the cement start to react, with the formation of calcium silicate hydrate and calcium hydroxide. This corresponds to the main period of hydration (Stage III), during which time concrete strengths increase.

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Study of aggregate dormancy and its effects on the properties of aggregates and concrete

2020. 12. 12.  made dormant and observed annually within the period of three-years (2015, 2016 and 2017). The cement used in this study was the 42.5N strength class, 19 mm coarse aggregate size and the fine aggregates being investigated. The laboratory tests performed were gradation size distribution

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National Precast Concrete Association Material Matters:

2015. 11. 17.  During the dormant period when the fresh concrete is plastic and able to be handled, prior to initial set, the action of set accelerators can last anywhere from 10 minutes in a hot mix to 2 hours for a cold mix. During the setting period, after initial set but prior to final set,

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Types of Admixtures of Concrete Cement Chemical,

2017. 3. 18.  When water is first added to cement there is a rapid initial hydration reaction, after which there is little formation of further hydrates for typically 2–3 hours. The exact time depends mainly on the cement type and the temperature. This is called the dormant period when the concrete

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Concrete: Quizes

2000. 3. 1.  The dormancy period of fresh concrete is the period during which the concrete is in a plastic state and the reaction is very, very slow. This state lasts from 1 to 3 hours and allows contractors to transport concrete to the job site and consolidate it before it hardens.

get price

Retarders for Concrete Mechanism, Types and Effects

Mechanisms of Retardation. Adding a retarder, dissolved in the mixing water or sprayed on the surface of the concrete, temporarily interrupts the hydration reactions, which creates a longer dormant period. The mechanisms that appear depend on the combination of the type of retarder and the type of cement.

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What is induction or dormant period in hydration of

During the hydration of cement heat evolves due to aluminates sulphates(present as components of cement) this heat can be ceases by added the gypsum but further

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Properties and effects of dormant aggregates on concrete

Aggregates used for concrete are sometimes abandoned on sites for extended periods of time. These aggregates are left dormant and exposed to harsh weather conditions before utilization. This study investigates the effect of aggregate dormancy of both fine aggregate (river sand) and coarse aggregate (gravel) on quality of concrete produced and its strength.

get price

Study of aggregate dormancy and its effects on the properties of aggregates and concrete

2020. 12. 12.  made dormant and observed annually within the period of three-years (2015, 2016 and 2017). The cement used in this study was the 42.5N strength class, 19 mm coarse aggregate size and the fine aggregates being investigated. The laboratory tests performed were gradation size distribution

get price

National Precast Concrete Association Material Matters:

2015. 11. 17.  During the dormant period when the fresh concrete is plastic and able to be handled, prior to initial set, the action of set accelerators can last anywhere from 10 minutes in a hot mix to 2 hours for a cold mix. During the setting period, after initial set but prior to final set,

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CIVL 1101 Part 8 Fresh Concrete

2021. 1. 22.  Both are gradual changes controlled by hydration. Fresh concrete will lose measurable slump before initial set and measurable strength will be achieved after final set. Setting is controlled by the hydration of C3S. The period of good workability is during the dormant period, (stage 2).

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The Study of Cement Hydration by Isothermal Calorimetry

2000. 8. 31.  optimisation of concrete with respect to frost resistance, durability, chemical resistance etc. is of great importance. Cement hydration is a strongly exothermal reaction that takes place in a number of stages (Young 1985): I. Rapid initial processes II. Induction (dormant) period III. Acceleration period IV Retardation period V. Long-term

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Concrete: Quizes

2000. 3. 1.  The dormancy period of fresh concrete is the period during which the concrete is in a plastic state and the reaction is very, very slow. This state lasts from 1 to 3 hours and allows contractors to transport concrete to the job site and consolidate it before it hardens.

get price

Retarders for Concrete Mechanism, Types and Effects

Mechanisms of Retardation. Adding a retarder, dissolved in the mixing water or sprayed on the surface of the concrete, temporarily interrupts the hydration reactions, which creates a longer dormant period. The mechanisms that appear depend on the combination of the type of retarder and the type of cement.

get price

Using a Concrete Curing Thermometer to Measure

2021. 4. 19.  How to Control Concrete Temperature During Mixing and Curing. Multiple methods currently exist to lessen the adverse effect of improper hydration temperatures. Two approaches, or a combination of both, can be taken to control the temperature during the dormant and strength-gain phase of the hydration process.

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Study of aggregate dormancy and its effects on the

These materials are left dormant and exposed to harsh weathering conditions before utilization. This study accessed the effects of aggregates dormancy on its properties quality when use. The study was carried out in three calendar years (2015, 2016 and 2017) to check weathering activities on dormant

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