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Plasticizer Cement Advanced concrete.pptx

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‫الرحیم‬ ‫الرحمن‬ ‫هللا‬ ‫بسمâ¶Ä¬
Islamic Emirate of Afghanistan Ministry of Higher Education Afghan International Islamic University Engineering Faculty Structural Engineering Ph.D. Program Plasticizer Cement Presented by: PhD Candidate Jamal Nasir Sharifi Lecturer: Professor Dr. Amanullah Faqiri Date: 2024/4/23
Plasticizer Cement ASTM C 1017 ï‚´ A material, which either increases workability of freshly mixed concrete without increasing water cement ratio or maintains workability with a reduced amount of water, is termed as water reducing admixture. ï‚´ As the name implies, the function of water reducing admixture is to reduce the water content of the mix, usually by 5 to 10%, sometimes (in concrete of very high workability) up to 15%. ï‚´ Thus, the purpose of using a Plasticizer in a concrete mix is to allow a reduction in the water cement ratio while retaining the desired workability or, alternatively, to improve its workability at a given water cement ratio. ï‚´ The actual reduction in water depends on dose of admixture, cement content, type of aggregate used, ratio of cement, fine and coarse aggregate etc. Therefore, the trial mixes containing an actual material to be used on the job are essential to achieve optimum properties.
Plasticizer
Why it is used? ï‚´ i) To increase the workability of the concrete without reducing the compressive strength or without changing water cement ratio. ï‚´ ii) This type of admixture is particularly useful when concrete pores are restricted either due to congested reinforcement or due to thin sections. ï‚´ iii) To obtain high strength with the same cement content by reducing water cement ratio. ï‚´ iv) To save the quantity of cement (approx. upto10%) can be achieved keeping the same water cement ratio and workability.
Effects of use of Plasticizers ï‚´ i) Reduced cement content keeping same water-cement ratio and workability. This will lead to economy. ï‚´ ii) Reduced water-cement ratio keeping same water content and same workability. This will lead to increase in strength. ï‚´ iii) Increased workability keeping same water cement ratio and cement content. This is specially required when workability retention for pumping etc. is needed. Dosage ranging from 0.15 to 0.6 percentages by weight of cement (different doses for different products) is recommended by manufacturers; however, it should be fixed as per design requirement and after site trials.
Super plasticizer Admixtures ï‚´ An admixture for mortar or concrete, which imparts very high workability or allows a large decrease in water content for a given workability. ï‚´ Normal water reducers are well-established admixtures called plasticizers in concrete technology. ï‚´ A normal water reducer is capable of reducing water requirement by 10 to 15%. ï‚´ Higher water reductions by incorporating larger amounts of these admixtures result in undesirable effects on concrete like bleeding, segregation and hardening. ï‚´ So, a new class of water reducers, chemically different from the normal water reducer and capable of reducing water content by about 30% has been developed. The admixtures belonging to this class are known as super plasticizers. Super plasticizers are, in fact, the extended version of plasticizers Typically by raising the slump from 75 mm to 200 mm, the mix remaining cohesive.
ï‚´ There are four main categories of super plasticizers based on their chemical composition: ï‚´ (i) Sulfonated melamine formaldehyde condensates ï‚´ (ii) Sulfonated naphthalene formaldehyde condensates ï‚´ (iii) Modified lignosulfonates ï‚´ (iv) Others such as sulfonic acid esters and carbohydrate esters.
Why it is used? ï‚´ (i) Cement content can be reduced to greater extent keeping the same water cement ratio. This will lead to economy. ï‚´ (ii) Water cement ratio can be reduced significantly keeping same cement content and workability. This will lead to increase in strength. ï‚´ (iii) Higher workability can achieved at very low water cement ratio, like casting concrete with heavy reinforcement. ï‚´ (iv) To reduce permeability. ï‚´ (v) Where early strength development is required in pre-stressed concrete or casting of floor, where early access for finishing equipment is required.
Plasticizer Cement Advanced concrete.pptx
Plasticizer Cement Advanced concrete.pptx
References ï‚´ 1. Gerry Bye, Paul Livesey, Leslie Struble (2011). "Admixtures and Special Cements". Portland cement, Third edition ï‚´ Hester, Weston T., Superplasticizers in Ready Mixed Concrete (A Practical Treatment for Everyday Operations), National Ready Mixed Concrete Association, Publication No. 158, Silver Spring, Maryland, 1979. ï‚´ Gebler, S. H., The Effects of High-Range Water Reducers on the Properties of Freshly Mixed and Hardened Flowing Concrete, Research and Development Bulletin RD081, Portland Cement Association, http://www.portcement.org/pdf_ files/RD081.pdf, 1982.

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Plasticizer Cement Advanced concrete.pptx

  • 2. Islamic Emirate of Afghanistan Ministry of Higher Education Afghan International Islamic University Engineering Faculty Structural Engineering Ph.D. Program Plasticizer Cement Presented by: PhD Candidate Jamal Nasir Sharifi Lecturer: Professor Dr. Amanullah Faqiri Date: 2024/4/23
  • 3. Plasticizer Cement ASTM C 1017 ï‚´ A material, which either increases workability of freshly mixed concrete without increasing water cement ratio or maintains workability with a reduced amount of water, is termed as water reducing admixture. ï‚´ As the name implies, the function of water reducing admixture is to reduce the water content of the mix, usually by 5 to 10%, sometimes (in concrete of very high workability) up to 15%. ï‚´ Thus, the purpose of using a Plasticizer in a concrete mix is to allow a reduction in the water cement ratio while retaining the desired workability or, alternatively, to improve its workability at a given water cement ratio. ï‚´ The actual reduction in water depends on dose of admixture, cement content, type of aggregate used, ratio of cement, fine and coarse aggregate etc. Therefore, the trial mixes containing an actual material to be used on the job are essential to achieve optimum properties.
  • 5. Why it is used? ï‚´ i) To increase the workability of the concrete without reducing the compressive strength or without changing water cement ratio. ï‚´ ii) This type of admixture is particularly useful when concrete pores are restricted either due to congested reinforcement or due to thin sections. ï‚´ iii) To obtain high strength with the same cement content by reducing water cement ratio. ï‚´ iv) To save the quantity of cement (approx. upto10%) can be achieved keeping the same water cement ratio and workability.
  • 6. Effects of use of Plasticizers ï‚´ i) Reduced cement content keeping same water-cement ratio and workability. This will lead to economy. ï‚´ ii) Reduced water-cement ratio keeping same water content and same workability. This will lead to increase in strength. ï‚´ iii) Increased workability keeping same water cement ratio and cement content. This is specially required when workability retention for pumping etc. is needed. Dosage ranging from 0.15 to 0.6 percentages by weight of cement (different doses for different products) is recommended by manufacturers; however, it should be fixed as per design requirement and after site trials.
  • 7. Super plasticizer Admixtures ï‚´ An admixture for mortar or concrete, which imparts very high workability or allows a large decrease in water content for a given workability. ï‚´ Normal water reducers are well-established admixtures called plasticizers in concrete technology. ï‚´ A normal water reducer is capable of reducing water requirement by 10 to 15%. ï‚´ Higher water reductions by incorporating larger amounts of these admixtures result in undesirable effects on concrete like bleeding, segregation and hardening. ï‚´ So, a new class of water reducers, chemically different from the normal water reducer and capable of reducing water content by about 30% has been developed. The admixtures belonging to this class are known as super plasticizers. Super plasticizers are, in fact, the extended version of plasticizers Typically by raising the slump from 75 mm to 200 mm, the mix remaining cohesive.
  • 8. ï‚´ There are four main categories of super plasticizers based on their chemical composition: ï‚´ (i) Sulfonated melamine formaldehyde condensates ï‚´ (ii) Sulfonated naphthalene formaldehyde condensates ï‚´ (iii) Modified lignosulfonates ï‚´ (iv) Others such as sulfonic acid esters and carbohydrate esters.
  • 9. Why it is used? ï‚´ (i) Cement content can be reduced to greater extent keeping the same water cement ratio. This will lead to economy. ï‚´ (ii) Water cement ratio can be reduced significantly keeping same cement content and workability. This will lead to increase in strength. ï‚´ (iii) Higher workability can achieved at very low water cement ratio, like casting concrete with heavy reinforcement. ï‚´ (iv) To reduce permeability. ï‚´ (v) Where early strength development is required in pre-stressed concrete or casting of floor, where early access for finishing equipment is required.
  • 12. References ï‚´ 1. Gerry Bye, Paul Livesey, Leslie Struble (2011). "Admixtures and Special Cements". Portland cement, Third edition ï‚´ Hester, Weston T., Superplasticizers in Ready Mixed Concrete (A Practical Treatment for Everyday Operations), National Ready Mixed Concrete Association, Publication No. 158, Silver Spring, Maryland, 1979. ï‚´ Gebler, S. H., The Effects of High-Range Water Reducers on the Properties of Freshly Mixed and Hardened Flowing Concrete, Research and Development Bulletin RD081, Portland Cement Association, http://www.portcement.org/pdf_ files/RD081.pdf, 1982.