All the products in the poromap line are made from hydraulic pozzolanicreaction binders. These stabilization additives provide an example of the classical pozzolanic stabilization reactions. The rate and mechanism of pozzolanic reaction of fly ash vary with curing temperature. The most often used mineral admixture in the modern concrete industry is the pozzolan. Adding pozzolans to an existing concrete mix without removing an equivalent amount of cement increases the paste content and decreases the watercement ratio. The objective of this research was to assess if different test methods for pozzolanic activity correlate with each other. Types of pozzolanic material definition and sources of. Pozzolanic definition of pozzolanic by the free dictionary. The increase in compressive strength could be attributed to the reduced water content, the filler effect, and the higher pozzolanic reaction.
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 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. Admixtures are added in concrete to improve the quality of concrete. 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.
This agrees well with the lowest compressive strength for concrete with 60% glass powder. Pozzolanicity is a very interesting issue regarding building materials, as a way to enhance mortars and concrete durability. 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. Typically pozzolans are used as cement replacements rather than cement additions. Pozzolans and the pozzolanic reaction springerlink. A high specific surface makes lime combination easier. Different types of natural and artificial pozzolans show pozzolanic activities that differ depending on the materials characteristics. The pozzolanic reaction is similar to the hydration reaction for di and tri calcium silicate. Pozzolanic reaction it will be assumed that all pozzolanic reactions are lime reactions with siliceous pozzolanic materials. The use of pozzolans in concrete concrete countertop. Evaluation of pozzolanic reactivity of calcined kaolinite. 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.
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. C is at 28 days or longer, and the pozzolanic reaction of fly ash in cement paste highly depends upon the curing temperature. The effectiveness of the use of fly ash in concrete depends on many factors including the following. 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. Pozzolan definition of pozzolan by the free dictionary. Physical properties and reactivity of pozzolans, and their influence. Evaluation of pozzolanic reactivity of calcined kaolinite by. The pozzolanic reaction between pozzolan and lime generates less heat, resulting in reduced thermal cracking when pozzolans are used to replace portland cement. Interaction between the pozzolanic reaction of fly ash and. Pdf on the kinetics of pozzolanic reaction in metakaolin. Dredge material stabilization using the pozzolanic or sulfo. However, few works have focused on the process or the morphology of the pozzolanic reaction products for lwfa.
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. Pozzolanic activity an overview sciencedirect topics. Physical properties and reactivity of pozzolans, and their. Synthesis and characterization of ca and na zeolites non. Index termsfly ash, pozzolanic reaction, cement paste, curing temperature, hydration.
The chemical shrinkage of pozzolanic reaction products authors. Reactions with aluminous pozzolanic materials will be briefly considered below. Pdf effect of pozzolanic additives on the strength development of. Analysing the pozzolanic reactivity of nanosilica in. Rha was passed through is 90 micron sieve and this was used for the research. The ph measurements were utilized to plot the activate energy curve and check the advance of. 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 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. Compressive strength of mortars due to pozzolanic reaction. Iowa state university ames, iowa 1970 signature was redacted for privacy.
Pozzolans are materials that consist predominantly of silica and alumina 3 and are able to combine. The propensity for alkalisilica reaction reaction with glass is decreased, or even virtually eliminated. Pozzolans are materials with an amorphous siliceous or siliceous. Pozzolanic reaction of glass powder and its influences on. It is observed by many research ers that there is an increase of compressive strength of mortar with the use of pozzolanic materials. The pozzolanic reaction converts a silicarich precursor with no cementing properties, to a calcium silicate, with good cementing properties. The fratini test is the basis of the actual en 1965 standard. Pozzolanic reactions of common natural zeolites with lime and. The pozzolanic activity of certain fly ashes and soil minerals. Other words that entered english at around the same time include.
Several authors 6,15 use mechanical properties, as the compressive strength of a cementpozzolan blend mor tar, as a measure for pozzolanic reaction. The pozzolanic reactivity analysis was performed with lime reaction according to the chapelle test using 1. Analcime, phillipsite, chabazite, erionite, mordenite and clinoptiloliterich tuffs were mixed with portlandite and water 1. 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. You can merge pdfs or a mix of pdf documents and other files. Pozzolanic reaction mechanism of rice husk ash in concrete. Evaluation of pozzolanic reactivity of artificial pozzolans. The ch content of the hydrated paste samples is calculated as at time t, ch1t 1 where m 420 t and m 540. 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. Metakaolin is prepared by calcination of enriched kaolin deposit senovo, bulgaria at temperature of.
Pozzolanic reaction is governed by the active silica and alumina contents and the specific surface of the pozzolan. In order to check the influence of temperature and morphology in pozzolanic reations, different types of silica were tested for a range of temperature. Ch and clays, reflect the intensity of pozzolanic reaction in the chclaywater system. 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. Pozzolanic reaction an overview sciencedirect topics. A type of ultralight pozzolanic reaction it will be assumed that all pozzolanic reactions are lime reactions with siliceous pozzolanic materials. The pozzolanic reaction is the chemical reaction that occurs in portland cement upon the addition of pozzolans. 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. Effect of calcination temperature on the pozzolanic activity. The hydrated phases produced during the pozzolanic reactions were c s h gels. Pozzolanic reactions of six principal clay minerals. Pozzolans combine with alkalis from cement that might otherwise combine with silica from aggregates, which would cause. At room temperature, the slower caoh 2 activation minimizes the reaction rate.
Use of rice straw ash as pozzolanic material in cement mortar. In this reaction insoluble calcium silicate hydrate and calcium. Rice farming activities is one of the main crops planted in malaysia. This property results from the reaction between calcium hydroxide and silica and alumina based materials. Analysing the pozzolanic reactivity of nanosilica in cement. Pdf the mixture of activated paper sludge and fly ash can successfully. Effect of curing temperature on pozzolanic reaction of fly.
Effects of different mineral admixtures on the properties of. Effect of calcination temperature on the pozzolanic. Results from an indirect pozzolanic activity test are often corroborated using direct tests to confirm that pozzolanic reactions are occurring 14, 20. Pozzolanic reactions of common natural zeolites with lime. The pozzolanic reaction between portlandite and different types of nearly pure natural zeolites was studied.
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. Determination of cement hydration and pozzolanic reaction. The dominate hydration product of portland cement is csh calcium silicate hydrate. Lime may be supplied in the form of lkd, quicklime, or hydrated lime. Pdf study of activation energy and reaction parameters. 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. When youre finished arranging, click combine files. 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. 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. Dredge material stabilization using the pozzolanic or. The reduction in soil settlement is attributed to the pozzolanic reaction in soiladditive interaction resulting in an increase in preconsolidation stress of stabilized soil.
Effects of different mineral admixtures on the properties. The pozzolanic reaction using portland cement as reagent has been assessed. Reaction products of clays and calcium hydroxide the quantity of reaction products or the remnants of starting material, i. At the glass powder content reaches 60%, the pozzolanic reaction would be limited by portlandite, the cement hydration products. Fly ash and river sand which were ground to have median particle sizes of 19.
Nov 20, 2010 pozzolanic reaction is governed by the active silica and alumina contents and the specific surface of the pozzolan. 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. Conclusions often depend on the interpretation of the start of the pozzolanic reaction. No physical test results obtained 1 specific gravity 2. A practical consequence of the pozzolanic reaction is the gradual hardening of pastes containing pozzolanic materials and lime. The chemical shrinkage of pozzolanic reaction products. Fa reaction with ordinary portland cement opc is a twostage process. 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. How to merge pdfs and combine pdf files adobe acrobat dc. Elevated curing temperatures lead to faster the onset and accelerated the rate of the main reaction linearly. 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. Details of the evaluation of ch content based on tg data can be found in marsh and day, 1988. The mass of pozzolanic reaction is lime reaction with alumina, silica.
Pozzolanic reaction of lightweight fine aggregate and its. The objective of this research is to study the compressive strength of mortar due to pozzolanic reaction of fly ash with different particle sizes. The pozzolanic activity of material is evaluated by chemical, physical, and mechanical methods. Fly ash, slag, silica fume, and natural pozzolans, chapter 3. A siliceous volcanic ash used to produce hydraulic cement. Click, drag, and drop to reorder files or press delete to remove any content you dont want. The total chemical shrinkage of silica fume and class f fly ash, both as pozzolanic materials. Strength increases as the amount of combined lime increases.
Compressive strength of mortars due to pozzolanic reaction of. Rha is an agricultural waste from rice milling process. Pozzolanic reactions of common natural zeolites with. Pozzolanic definition and meaning collins english dictionary. Third, the quicklime hydration reaction is exothermic, an d the heat evolved can help speed evaporation of additional moisture. Nov 15, 2014 the pozzolanic reactivity analysis was performed with lime reaction according to the chapelle test using 1. The main mechanism involves the transportation of calcium hydroxide via water within the soil to combine with the aluminate andor silicate clay minerals duxson. Dredge material stabilization using the pozzolanic or sulfopozzolanic reaction of lime byproducts to make an engineered structural fill joel h. Hydrated lime caoh2, plus a supplement of pozzolanic class f fly ash, reacts with the dm silt and clay. The pozzolanic reaction is 25% based on a silica equivalent. Pdf thermodynamic evaluation of pozzolanic reactions between.
In opposition to fratini methodology, chapelle 1958. The kinetics of pozzolanic reaction metakaolinlime is studied in the present work. Determination of cement hydration and pozzolanic reaction extents for flyash cement pastes article pdf available in construction and building materials 271. 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. Recently, incorporation of cement replacement material crm in concrete has gained considerable attention throughout the world. View pozzolanic materials research papers on academia. 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. In the first stage, during the early curing, the primary reaction is with caoh 2. 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. Diffraction files pdf from the international centre for diffraction data icdd files. It is the main reaction involved in the roman concrete invented in ancient rome and used to build, for example, the pantheon. A blend of portland cement and pozzolans has been commonly used to deal with. Assessment of pozzolanic activity using methods based on.
689 543 1212 1551 1303 312 467 1307 1599 1309 467 529 1438 1482 808 779 1322 662 1404 1531 51 794 1185 1387 826 286 217 1115 1455 909 126 791 1243 477 5 1400 670