Results from an indirect pozzolanic activity test are often corroborated using direct tests to confirm that pozzolanic reactions are occurring 14, 20. Recently, incorporation of cement replacement material crm in concrete has gained considerable attention throughout the world. Evaluation of pozzolanic reactivity of artificial pozzolans. The fratini test is the basis of the actual en 1965 standard. No physical test results obtained 1 specific gravity 2. Pozzolanic reactions of six principal clay minerals. Pdf effect of pozzolanic additives on the strength development of. At the glass powder content reaches 60%, the pozzolanic reaction would be limited by portlandite, the cement hydration products. All the products in the poromap line are made from hydraulic pozzolanicreaction binders. Nov 20, 2010 pozzolanic reaction is governed by the active silica and alumina contents and the specific surface of the pozzolan. However, according to massazza 8, this only applies to the earlier stages of the pozzolanic reaction whereas at longer ages, the pozzolanic reaction is mainly controlled.
Effect of calcination temperature on the pozzolanic activity. However, every natural pozzolan with a strong acidic character does not show pozzolanic activity 14, and hence the assessment of pozzolanic activity of a given natural pozzolan is a prerequisite for its use in the cement industry. In this reaction insoluble calcium silicate hydrate and calcium. A more formal definition is given by astmc61884 as a siliceous or siliceous and aluminous material which, in itself, possesses little or no cementitious value but which will, in finely divided form in the. A high specific surface makes lime combination easier. Pozzolanic definition and meaning collins english dictionary. Pozzolans are materials with an amorphous siliceous or siliceous. Use of rice straw ash as pozzolanic material in cement mortar. You can merge pdfs or a mix of pdf documents and other files. Evaluation of pozzolanic reactivity of calcined kaolinite. Elevated curing temperatures lead to faster the onset and accelerated the rate of the main reaction linearly. In this study, tests results from thermogravimetric experiments and isothermal hydration tests are first analyzed by assuming that the fly ash only promotes the cement. Reactions with aluminous pozzolanic materials will be briefly considered below.
Reaction products of clays and calcium hydroxide the quantity of reaction products or the remnants of starting material, i. Nov 15, 2014 the pozzolanic reactivity analysis was performed with lime reaction according to the chapelle test using 1. The pozzolanic reaction is the chemical reaction that occurs in portland cement upon the addition of pozzolans. The pozzolanic reactivity analysis was performed with lime reaction according to the chapelle test using 1. Effects of different mineral admixtures on the properties of. Pozzolanic reaction of lightweight fine aggregate and its. Analcime, phillipsite, chabazite, erionite, mordenite and clinoptiloliterich tuffs were mixed with portlandite and water 1. Pozzolanic reactions of common natural zeolites with lime. Typically pozzolans are used as cement replacements rather than cement additions. The pozzolanic reaction converts a silicarich precursor with no cementing properties, to a calcium silicate, with good cementing properties.
Conclusions often depend on the interpretation of the start of the pozzolanic reaction. The mass of pozzolanic reaction is lime reaction with alumina, silica. Effect of calcination temperature on the pozzolanic. The propensity for alkalisilica reaction reaction with glass is decreased, or even virtually eliminated. Lime may be supplied in the form of lkd, quicklime, or hydrated lime.
The dominate hydration product of portland cement is csh calcium silicate hydrate. The chemical shrinkage of pozzolanic reaction products. Effect of curing temperature on pozzolanic reaction of fly. Evaluation of pozzolanic reactivity of calcined kaolinite by. Several authors 6,15 use mechanical properties, as the compressive strength of a cementpozzolan blend mor tar, as a measure for pozzolanic reaction. Pdf the mixture of activated paper sludge and fly ash can successfully. Pozzolanic reaction it will be assumed that all pozzolanic reactions are lime reactions with siliceous pozzolanic materials. Poromap line the poromap line of products is the ideal solution for restoring masonry with rising damp and structures damaged by the crumbling effect of sulphate salts, chlorides and nitrates. Adding pozzolans to an existing concrete mix without removing an equivalent amount of cement increases the paste content and decreases the watercement ratio. The ph measurements were utilized to plot the activate energy curve and check the advance of. The pozzolanic reaction is 25% based on a silica equivalent.
A pozzolan, and there are many of them, is defined as siliceous or siliceous and aluminous materials which in themselves possess little or no cementitious value but will, in finely divided form and in the presence of moisture, chemically react with calcium hydroxide at ordinary temperatures to. Click, drag, and drop to reorder files or press delete to remove any content you dont want. The use of pozzolans in concrete concrete countertop. Different types of natural and artificial pozzolans show pozzolanic activities that differ depending on the materials characteristics. Pozzolans are materials that consist predominantly of silica and alumina 3 and are able to combine. A type of ultralight pozzolanic reaction it will be assumed that all pozzolanic reactions are lime reactions with siliceous pozzolanic materials.
The pozzolanic activity of material is evaluated by chemical, physical, and mechanical methods. The reduction in soil settlement is attributed to the pozzolanic reaction in soiladditive interaction resulting in an increase in preconsolidation stress of stabilized soil. The pozzolanic reaction using portland cement as reagent has been assessed. Pozzolanic activity an overview sciencedirect topics. The rate of reaction of pozzolanic material with calcium hydroxide depends on the specific surface area of the pozzolan, watersolid ratio, and alkaline content in portland cement and temperature. Pozzolanic reaction mechanism of rice husk ash in concrete. Interaction between the pozzolanic reaction of fly ash and. The rate of the pozzolanic reaction is dependent on the intrinsic characteristics of the pozzolan such as the specific surface area, the chemical composition and the active phase content. Index termsfly ash, pozzolanic reaction, cement paste, curing temperature, hydration.
How to merge pdfs and combine pdf files adobe acrobat dc. Assessment of pozzolanic activity using methods based on. Pdf on the kinetics of pozzolanic reaction in metakaolin. C is at 28 days or longer, and the pozzolanic reaction of fly ash in cement paste highly depends upon the curing temperature. Calcite production depends on the presence of portlandite therefore, it was assumed that, if calcite was being formed, portlandite was still available and thus the pozzolanic reaction still active. Dredge material stabilization using the pozzolanic or sulfo. The increase in compressive strength could be attributed to the reduced water content, the filler effect, and the higher pozzolanic reaction.
Rha is an agricultural waste from rice milling process. In opposition to fratini methodology, chapelle 1958. The pozzolanic activity of taftan pozzolan was also evaluated by determining its strength activity index with portland cement at 7 and 28 days astm c311. When youre finished arranging, click combine files. Pozzolanic reaction of glass powder and its influences on.
It is known that the commonly used crm in current concrete industry is silica fume sf, pulverized fuel ash pfa and rice husk ash rha. Third, the quicklime hydration reaction is exothermic, an d the heat evolved can help speed evaporation of additional moisture. Iowa state university ames, iowa 1970 signature was redacted for privacy. Other words that entered english at around the same time include. The rate of the pozzolanic reaction is dependent on the intrinsic characteristics of the pozzolan such as the specific surface area, the chemical composition and. Physical properties and reactivity of pozzolans, and their influence. Rice farming activities is one of the main crops planted in malaysia. The conventional method for alkali activation of fly ash utilizes caoh 2 and naoh for the formation of pozzolanic material and fly ash zeolites, respectively.
Pozzolanic reactions of common natural zeolites with. Pozzolanic reactions in synthetic fly ashes a dissertation submitted to the graduate faculty in partial fulfillment of the requirements for the degree of doctor of philosophy major subject. Fa reaction with ordinary portland cement opc is a twostage process. Types of pozzolanic material definition and sources of. Synthesis and characterization of ca and na zeolites non. The objective of this research was to assess if different test methods for pozzolanic activity correlate with each other.
Hydrated lime caoh2, plus a supplement of pozzolanic class f fly ash, reacts with the dm silt and clay. Compressive strength of mortars due to pozzolanic reaction of. Metakaolin is prepared by calcination of enriched kaolin deposit senovo, bulgaria at temperature of. Pozzolanicity is a very interesting issue regarding building materials, as a way to enhance mortars and concrete durability.
Determination of cement hydration and pozzolanic reaction. A practical consequence of the pozzolanic reaction is the gradual hardening of pastes containing pozzolanic materials and lime. The hydrated phases produced during the pozzolanic reactions were c s h gels. The objective of this research is to study the compressive strength of mortar due to pozzolanic reaction of fly ash with different particle sizes. Pozzolans and the pozzolanic reaction springerlink. Analysing the pozzolanic reactivity of nanosilica in cement. The effectiveness of the use of fly ash in concrete depends on many factors including the following. It is observed by many research ers that there is an increase of compressive strength of mortar with the use of pozzolanic materials. A simple everyday definition of pozzolan could be a finely powdered material which can be added to lime mortar or to portland cement mortar to increase durability. Analysing the pozzolanic reactivity of nanosilica in. View pozzolanic materials research papers on academia. Rha was passed through is 90 micron sieve and this was used for the research.
Founded in 1904 and headquartered in farmington hills, michigan, usa, the american concrete institute is a leading authority and resource worldwide for the development, dissemination, and adoption of its consensusbased standards, technical resources, educational programs, and proven expertise for individuals and organizations involved in concrete design. A siliceous volcanic ash used to produce hydraulic cement. The pozzolanic materials are generally high in sio 2 and al 2 o 3 and low in cao, with or no reactivity when immersed in water. The total chemical shrinkage of silica fume and class f fly ash, both as pozzolanic materials.
Pdf study of activation energy and reaction parameters. To investigate the pozzolanic reaction of lwfa, researchers ground the lwfa into a fine powder and immersed it in the pore solution at 70 c, which indicated that heat curing can improve the pozzolanic reactivity of lwfa. The kinetics of pozzolanic reaction metakaolinlime is studied in the present work. Sodiumbased fly ash zeolites say, nazeolite mostly employ naoh the highgrade mineralizer and alkali for activation of fly ash before its application as an absorbent.
The pozzolanic reaction is similar to the hydration reaction for di and tri calcium silicate. Pozzolanic reactions of common natural zeolites with lime and. The pozzolanic activity of certain fly ashes and soil minerals. Pozzolanic additives derived from lightly fired and finely crushed clay products, such as clay tile or brick, were used by the romans and combinations of nonhydraulic lime and low temperature brick dusts have been used over a long period of time. The pozzolanic reactivity of nanosilica is calculated based on the ch content of the cement paste samples at different ages. This property results from the reaction between calcium hydroxide and silica and alumina based materials. Pozzolans combine with alkalis from cement that might otherwise combine with silica from aggregates, which would cause. Effect of calcination temperature on the pozzolanic activity of brazilian sugar cane bagasse ash scba daniel veras ribeiro a, marcio raymundo morellib adepartment of materials science and technology, federal university of bahia ufba, rua aristides novis, 02, federacao, cep 40210630, salvador, ba, brazil. The ch content of the hydrated paste samples is calculated as at time t, ch1t 1 where m 420 t and m 540. Pozzolanic reaction an overview sciencedirect topics.
The pozzolanic reaction between portlandite and different types of nearly pure natural zeolites was studied. The pozzolanic reaction between pozzolan and lime generates less heat, resulting in reduced thermal cracking when pozzolans are used to replace portland cement. Ch and clays, reflect the intensity of pozzolanic reaction in the chclaywater system. This paper presents the results of three pozzolanic reactivity test methods, including chapelle test, fratinni test and strenght activity index sai methods, that were applied to metakaolin and other thermally treated clay, ashes and glass. Dredge material stabilization using the pozzolanic or. At room temperature, the slower caoh 2 activation minimizes the reaction rate. Finally, hydrated lime solubilizes silicates and aluminates at high ph which initiates pozzolanic reactions and sulfo pozzolanic r eactions when sulfates or sulfites are present.
Pozzolan definition of pozzolan by the free dictionary. Fly ash and river sand which were ground to have median particle sizes of 19. Compressive strength of mortars due to pozzolanic reaction. Strength increases as the amount of combined lime increases. The main mechanism involves the transportation of calcium hydroxide via water within the soil to combine with the aluminate andor silicate clay minerals duxson.
This agrees well with the lowest compressive strength for concrete with 60% glass powder. Pozzolanic definition of pozzolanic by the free dictionary. A blend of portland cement and pozzolans has been commonly used to deal with. Fly ash, slag, silica fume, and natural pozzolans, chapter 3. These stabilization additives provide an example of the classical pozzolanic stabilization reactions. It is the main reaction involved in the roman concrete invented in ancient rome and used to build, for example, the pantheon. However, few works have focused on the process or the morphology of the pozzolanic reaction products for lwfa. Effects of different mineral admixtures on the properties. The most often used mineral admixture in the modern concrete industry is the pozzolan. Pozzolanic reaction is governed by the active silica and alumina contents and the specific surface of the pozzolan.
The chemical shrinkage of pozzolanic reaction products authors. Pdf thermodynamic evaluation of pozzolanic reactions between. Mineral admixtures include fly ash fa, silica fume sf, ground granulated blast furnace slag ggbs, metakaolin mk, and rice husk ash rha which possess certain characteristics through which they influence the properties of concrete differently. In the first stage, during the early curing, the primary reaction is with caoh 2. Physical properties and reactivity of pozzolans, and their. Determination of cement hydration and pozzolanic reaction extents for flyash cement pastes article pdf available in construction and building materials 271.