10.105 – EFFLORESCENCE
High-Reactivity Metakaolin
Engineered Mineral Admixture for Use with Portland Cement

Advanced Cement Technologies’ PowerPozzTM High Reactivity Metakaolin is a manufactured pozzolanic mineral admixture which significantly enhances many performance characteristics of cement-based mortars, concretes and related products.

PowerPozzTM, derived from purified kaolin clay, is a white, amorphous, aluminosilicate which reacts readily with calcium hydroxide to form compounds with cementitious value. PowerPozzTM is subjected to strict process quality controls to assure product uniformity and consistent performance. PowerPozzTM is produced to 1S0 9002 Certification Standards and meets the specification of ASTM C-618 – Class N Pozzolans.

Used at 5 – 15% by weight of cement, PowerPozzTM will provide: increased strength; reduced permeability; greater durability; and is effective in mitigating efflorescence and degradation caused by alkali-silica reaction (ASR).

Problem Statement

The phenomenon, commonly known as efflorescence, occurs when calcium hydroxide (free lime), a soluble reaction by-product of the hydration process of ordinary portland cement (OPC), is carried to the surface of cement-based products by migrating water. Exposed to the atmosphere, calcium hydroxide reacts with carbon dioxide to form calcium carbonate deposits which remain apparent as unsightly, whitish stains. Too often, efflorescence shows up to severely dampen the aesthetic appeal of otherwise successful masonry and composite projects.

Most common and problematic in masonry construction and architectural precast products, efflorescence is a persistent problem which has brought about a situation where masonry and precast design flexibility has been unnecessarily limited.

Two forms of Efflorescence have been identified – Primary and Secondary. They are distinguished by the point in time at which they occur in relation to the curing process.

• Primary efflorescence occurs during the curing process. Excess water in the matrix bleeds to the surface where it eventually evaporates, leaving behind deposits of calcium hydroxide crystals (Ca(OH)2) which, when exposed to the carbon dioxide (CO2) in the air, form calcium carbonate (CaCO3) in the surface pores.
• Secondary efflorescence occurs in cured concretes and composites, which are in contact with moisture or are subjected to cycles of re-wetting and drying. Moisture penetrates into, and leaches from, the matrix, dissolving soluble calcium hydroxide (Ca(OH2) that remains as a normal byproduct of portland cement hydration. Upon subsequent drying, the water, with lime in solution, can migrate to the surface (atmosphere) where, upon evaporation, leaves deposits of calcium hydroxide (Ca(OH)2 and subsequently, calcium carbonate (CaCO3).

The PowerPozzTMSolution

• Eliminate Free Lime from the system through rapid Pozzolanic Reaction,
• Increase the density and Reduce the Porosity and Permeability of the paste system,
• Reduce the Cement Content with Pozzolan Substitution 5 – 15% (the Dilution Effect).

Pozzolanic Reactivity

PowerPozzTMis a lime-hungry pozzolan that reacts with free calcium hydroxide to form stable, insoluble, strength-adding, cementitious compounds.

When PowerPozzTMHRM (AS2) reacts with calcium hydroxide (CH), a cement hydration byproduct, a pozzolanic reaction takes place whereby new cementitious compounds, (C2ASH8) and (CSH), are formed. These newly formed compounds will contribute cementitious strength and enhanced durability properties to the system in place of the otherwise weak and soluble calcium hydroxide.

Unlike other commercially available pozzolanic materials, PowerPozzTMHRM is a quality-controlled, manufactured material. It is not a byproduct of an unrelated industrial process. PowerPozzTMhas been engineered and optimized to contain a minimum of impurities and to react efficiently with cement’s hydration byproduct –calcium hydroxide. As determined by the Chappelle test(1), Table 1 summarizes the relative reactivities of six different pozzolans, including an HRM sample(2).

Primary efflorescence can be reduced by using PowerPozzTM at 5 – 15% replacement of cement by weight. Care must be taken to follow good curing.

practices that will minimize evaporation during curing. Low water cement ratios, plastic vapor barriers, delayed demolding, high humidity (or steam curing) are now, and have long been, recommended as good concrete curing practice. The use of High Reactivity Metakaolin works to the root of the efflorescence problem by eliminating the calcium hydroxide from the system. Once fully cured, an optimized HRM-formulated product cannot exhibit Secondary Efflorescence as virtually all of the available free lime has been chemically combined by pozzolan.

The ability of metakaolin to combine with calcium hydroxide is well-researched and documented. Larbi and Bijen(3) and Jones, et al(4) have shown that the pozzolanic reaction with pure metakaolin is rapid. In fact, it is apparent that the rate of reaction approaches that of cement hydration and subsequent lime liberation. Figure 1 shows the reaction curves and shows that metakaolin, at 20%, virtually eliminated Ca(OH)2 from the system at 14 days.

Reduced Permeability

Concrete’s porosity, pore interconnectivity, and overall permeability to fluids have direct influence on the concrete’s ultimate durability and useful service life. Where quality concretes, mortars and other cement-based products are produced with careful control of materials and water to cement ratios, performance can be significantly enhanced by the addition of highly reactive pozzolans. The addition of PowerPozzTM HRM to these materials, at a 5 – 15% replacement by weight of cement will contribute to a more compact arrangement of cementitious products where increased paste densities, mechanical interlock and paste-aggregate bond are the result. The key to maximum results here, as it is with the addition of any finely divided material to concrete in wet or dry casting processes, is a fully dispersed and homogenous matrix of ingredient materials.

In addition, the pozzolanic reaction, as described above, has a direct and significant influence on the material’s service permeability. As soluble hydration byproducts in a non-pozzolan enriched concrete are leached out by migrating moisture, they leave behind opened and more interconnected pore systems which will set the stage for an increased risk and rate of efflorescence discoloration, fading and staining. By chemically combining with calcium hydroxide, the pore system is rendered much more stable.

The surface texture of a concrete, stucco, mortar or related product can also be enhanced with a PowerPozzTMaddition. Sharper, stronger edges and details with a “tightened” surface are possible. It is conceivable that with a finer pore system on the surface, any occurrence of efflorescence or related fading of pigmented products would be less apparent as calcium carbonate deposits tend to be more obvious in products with larger, more open surface pores. These effects are principally attributed to the efficient size, shape and micropacking effect of PowerPozzTM’sclayparticles which contribute to a more dense and internally cohesive paste structure.

Cement Replacement- The Dilution Effect

PowerPozzTMhas the potential to produce high strengths in cement-based products at 5 – 15% replacement by weight of cement. As such, it is common to see increases in concrete or mortar compressive strengths (>20%) such that a further cement reduction beyond pound for pound cement replacement can be taken if strength gains of this degree are not required or beneficial. It is possible for PowerPozzTM to replace cement by weight at 1:2 to 1:3; this would, of course, require trial mixes with specific materials to confirm the exact formula. It is in this further cement reduction that the dilution effect becomes significant. This is of particular significance for stucco products (eg. where strength is of lower concern), but would need to be balanced against workability and related properties as a function of total cementitious paste content.

PowerPozzTMfeatures:

• Rapid reaction. The potential to react with more than its own weight equivalent in calcium hydroxide.
• A minimum of impurities.
• Stable-to-enhanced early strength performance (< 24 hours).

This unique package of features and benefits makes PowerPozzTMstand out within the world of admixtures as the performance leader and preferred pozzolan for use in quality and high performance architectural and structural applications – especially where engineering properties, aesthetics and durability are important.

All information, while provided in good faith, with every effort made to assure accuracy, is provided by Advanced Cement Technologies at no charge, and without warranty –express or implied. Data given, unless otherwise stated, are based on standard testing procedures which are available on request. Variations do occur in individual tests and the results stated herein cannot be taken for minima or maxima for specification purposes.

As we cannot anticipate all possible applications of our product, nor variations in manufacturing equipment, formulae, methods, or practices, we guarantee only that the product will meet the specifications of Advanced Cement Technologies at the time of sale. Advanced Cement Technologies reserves the right to change specifications should it become necessary. The product is sold without express or implied warranty, with all warranties of fitness of purpose and merchantability being disclaimed, and on condition that the purchaser is responsible for the determination of the product’s suitability for a particular purpose.

Statements concerning the possible use of our product are not intended as recommendations for use. No liability is accepted for any infringements of any existing or future patents.

All products sold, unless otherwise stated, will be subject to general sales conditions, which are supplied with all quotations and order confirmations.

REFERENCES

1. LARGENT, R. Bull. Liasons Lab. Pont Chausees, v.93, 1978, pp. 63.
2. New Pozzolanic Materials For The Concrete Industry ECC International – Europe.
3. LARBI, J.A. and BIJEN, J.M. PhD Thesis, Delft University, 1991.
4. JONES, T.R., WALTERS, G.V. and KOSTUCH, J.A. 9th Int. Conf. AAR in Concrete, v.1, 1992, pp. 485-496

10.104 – ALKALI-SILICA REACTION (ASR)
High Reactivity Metakaolin
Engineered Mineral Admixture for Use with Portland Cement

Advanced Cement Technologies’ PowerPozz™ (a High-Reactivity Metakaolin) is a manufactured pozzolanic mineral admixture which significantly enhances many performance characteristics of cement-based mortars, concrete, and related products.

Derived from purified kaolin clay, PowerPozz™ is a white, amorphous, aluminosilicate which reacts readily with calcium hydroxide to form compounds with cementitious value.

Background – The ASR Problem

Quality concrete is a carefully selected composition of materials which, when properly manufactured, proportioned, mixed, placed, consolidated, finished and cured will have sufficient strength and durability in accordance with the desired application. Unfortunately, a problem exists and has long been identified where cement alkalis, while being important to the concrete’s strength development, can be, under certain circumstances, principally and directly contributory to degradation and loss of durability.

ASR can be explained as the situation where cement alkalis react with certain forms of silica in the aggregate component of a concrete, forming an alkali-silica gel at the aggregates surface. This formation, often referred to as “reaction rim” has a very strong affinity for water, and thus has a tendency to swell. These expanding compounds can cause internal pressures sufficiently strong to cause cracking of the paste matrix, which can then result in a compromised concrete with an open door to an increasing rate of deterioration.

For the alkali silica reaction to occur and produce a potentially expansive gel, Ca, OH, reactive silica, water, and soluble metal alkali ions need to be present. The Ca(OH)2 is the free lime by-product of ordinary portland.

cement (OPC) hydration. Reactive phases of silica are found in some sources of construction aggregates with wide regional variations. The soluble alkali ions may be present in the pore solution of the concrete (the amount being primarily dependent on cement alkalinity) and/or from external sources of salts such as seawater, or road de-icing substances.

The worldwide costs of ASR degradation are extremely high. Regional manifestations of these costs are seen in: remedial repairs in already deteriorating structures; new construction (where costs are impacted dramatically in use in imported, low-alkali cement and /or imported non-reactive aggregates); and in the less tangible impact on structure life cycle and overall owner and user utility.

The PowerPozz™ Solution

When a pure form of Metakaolin is employed as a pozzolanic mineral admixture at 10 -15% weight of cement, the calcium hydroxide level can be reduced sufficiently to render any gels that are formed as non-expansive (1,2). The protection is further enhanced in view of the Metakaolin addition’s effect on overall reduced concrete permeability and in a slight reduction in the alkalinity of the pore solution.

Figure 1, illustrates the research by Jones et al (1,2) and shows the effect of High Reactivity Metakaolin in mitigating the expansion that is very clearly the result in control (plain OPC) samples under the same curing and exposure conditions. After 32 months of curing at 100% relative humidity, the control and HRM samples were immersed in a saturated sodium chloride solution to induce expansion. The expansion is eliminated in this study at a 15% replacement of cement by weight with a HRM.

Tests have been performed using PowerPozz™ HRM to study the potential to mitigate the effects of ASR in mortar bars. The study reported here, conducted by Jacques Whitford and Associates, was performed in accordance with Canadian Test Standard CSA A23.2-25A (Accelerated Mortar Bar Test) which is similar to ASTM C1260. The evaluation was under the direction of Mr. Wilbert S. Langley (3). Results are illustrated in Figure 2.

The test involved a control (plain OPC) mix, a 20% Class F flyash mix, and PowerPozz™ mixes at 5, 10, and 20% replacement. The results show that with a known very reactive aggregate, PowerPozz™, at 10%, dramatically reduced the expansion versus the control and flyash formulations. At 20%, expansion was virtually eliminated.

Referenced Documents:

1. 1. Jones, T.R. , Walters, G.V., and Kostuch, J.A. 9th International Conference on AAR in Concrete, v.1, 1992, pp. 485-496.
   2. Walters, G.V., and Jones, T.R. 2nd International Conference on Durability of Concrete, Canada, ed. V.M. Malhotra, 1991, pp. 941-953.
   3. Test Report – Jacques Whitford Materials Ltd., August 29, 1995.

All information, while provided in good faith, with every effort made to assure accuracy, is provided at no charge, and without warranty – express or implied. Data given, unless otherwise stated, are based on standard testing procedures which are available on request. Variations do occur in individual tests and the results stated herein cannot be taken for maxima or minima for specification purposes.

As we cannot anticipate all possible applications of our products, nor variations in manufacturing equipment, formulae, methods, or practices, we guarantee only that the products will meet the specifications of Advanced Cement Technologies at the time of sale. Advanced Cement Technologies reserves the right to change specifications should it become necessary. Products are sold without warranty, express or implied, with all warranties of fitness of purpose and merchantability being disclaimed, and on condition that the purchaser is responsible for the determination of each product’s suitability for a particular purpose.

Statements concerning the possible use of our products are not intended as recommendations for use. No liability is accepted by Advanced Cement Technologies for any infringements of any existing or future patents.

Products sold, unless otherwise stated, will be subject to the general terms and sales conditions of Advanced Cement Technologies.

10.103 – PARTICLE SIZE DISTRIBUTION (PSD)
High Reactivity Metakaolin (HRM)
Engineered iMineral Admixture for Use with Portland Cement

Advanced Cement Technologies’ PowerPozzTM HRM is a manufactured pozzolanic mineral admixture which significantly enhances many performance characteristics of cement-based mortars, concretes, and related products.

PowerPozzTM, derived from purified kaolin clay, is a white, amorphous, alumino-silicate which reacts aggressively with calcium hydroxide to form compounds with cementitious value.

Produced under ISO 9002, PowerPozzTM is subjected to strict process quality controls to assure product uniformity and consistent performance.

Used at 5-15% replacement of cement by weight, PowerPozzTM will contribute to: increased strength; reduced permeability; greater durability; and effective control of efflorescence and degradations caused by alkali-silica reaction (ASR) in concrete.

PowerPozzTM is milled and classified to exacting particle size distribution specifications.

In optimizing the PSD for PowerPozzTM, a number of factors were considered to be important:

10.102 –POZZOLANIC ACTIVITY INDEX
(COMPRESSIVE STRENGTH OF MORTARS)
High Reactivity Metakaolin (HRM)
Engineered Mineral Admixture for Use with Portland Cement

Advanced Cement Technologies’ PowerPozz™ High Reactivity Metakaolin is a manufactured pozzolanic mineral admixture which significantly enhances many performance characteristics of cement-based mortars, concretes and related products.

PowerPozz™, derived from purified kaolin clay, is a white, amorphous, alumino-silicate which reacts aggressively with calcium hydroxide, a normal cement hydration byproduct, to form compounds with cementitious value.

Testing Program

Advanced Cement Technologies has performed an evaluation of the performance of PowerPozz™HRM in cement mortars. The purpose of the testing (in accordance with ASTM C-311 / ASTM C-618) was to demonstrate the pozzolanic activity index of PowerPozzTMHRM over that of a control, or in some cases, as compared to other pozzolans.

The evaluations, conducted at the facilities of AGRA Earth and Environmental in Vancouver, B.C., Canada,were conducted in three phases:

In Phase 1, PowerPozz™was used in varying concentrations (5,10, 15%) and compared to the same concentrations of silica fume and to a plain cement control. Strengths and the variations in required superplasticizer dosage were examined.

In Phase 2, the mixes were produced with a range of different pozzolans, including PowerPozz™without superplasticizers. The water addition and therefore water to binder ratios were allowed to vary to achieve similar flows. Effects on water demand and strength were examined.

In Phase 3, the compressive strength of a plain cement mortar was compared with the strength gain of a mortar in which 10% of the cement was replaced with PowerPozzTMHRM. In this study, a dry superplasticizer was added to both the control and the test mixes at a constant dosage. Both the control and test mixes were produced at a water / binder ratio of 0.40 and a sand / binder ratio of 2.75. Compressive strengths presented are the averages for 3 cubes at each of the 4 age intervals (1,3,7,28 days).

PHASE 1

Methodology

In this study, 9 mortar mixes were produced: Two of the mixes were Class F Flyash/HRM combinations and will be reported separately. For the remaining 7 mixes, the following cementitious materials were used:

Mix 1:Type 1 Ordinary Portland Cement (Control)
Mix 2:OPC / 5% PowerPozz™HRM
Mix 3:OPC / 10% PowerPozz™HRM
Mix 4:OPC / 15% PowerPozz™HRM
Mix 5:OPC / 5% Silica Fume
Mix 6:OPC / 10% Silica Fume
Mix 7:OPC / 15% Silica Fume

The percentages of supplemenntary cementing materials were replacementsby weight of portland cement, not additions.

The mortars were produced with a water : binder ratio of 0.40.

The compressive strength results reported are the averages of two cubes.

Phase 1 Results

Results from Phase 1 are reported in Table 1.

Project: Comparative Strength Testing of PowerPozz™High Reactivity Metakaolin

Subject: Strength Activity Index with Portland Cement (ASTM C-311)

Phase 1 Results & Discussion

The results show that both mineral admixtures show progressive increases in strength with increasing percentages of replacement, up to the 15% level.

With PowerPozz™at 5% replacement, the strength increase is 10% over control. At 10% and 15% replacements, PowerPozz™contributed to 22% and 28% gains respectively as compared to the control mix.

The results indicate that increasing loading rates of PowerPozz™contribute to higher strengths.

These results also indicate that PowerPozz™is most efficient within the range of 10 +2%. At 5% PowerPozz™, a 2% increase in strength is realized per percent PowerPozz™. This increases to a 2.2% increase in strength per percent PowerPozz™at 10% replacement and decreases slightly to 1.9% per percent PowerPozz™at the 15% replacement level.

In comparing the PowerPozz™HRM mixes to those produced with silica fume, PowerPozz™mortars were generally stronger at three days, approximately the same at seven days and slightly lower at 28 days.

These results show that PowerPozz™is comparable to silica fume in terms ofcompressive strength development but does so with a much lower water demand. Therefore, the PowerPozz™mortars required a significantly lower (half) dosage of superplasticizer to maintain flow and stable water: cementitious ratio. The pozzolanic activity results withoutthe use of superplasticizers are examined in Phase 2.

It was observed that with PowerPozz™being white in color, it produced mortars which were fairly normal in appearance, whereas those produced with silica fume had a characteristic dark gray color.

PHASE 2

Methodology

In the second study, the mortars were produced in accordance withASTM C-311.One control (plain OPC) mix was produced, and all other supplementary cementing materials were used at 7.5% replacement by weight of cement.

Five mixes are reported here. Of the five mixes one was the control, one included silica fume, andthree were produced with metakaolins. Of the three HRM products used, one is PowerPozz™, and the other two are other commercially available metakaolins.

Mix 1:OPC -Ordinary Portland Cement (Control)
Mix 2:OPC / Metakaolin A
Mix 3:OPC / Metakaolin B
Mix 4:OPC / PowerPozz™
Mix 5:OPC / Silica Fume

The control mixwas produced with a water : cement ratio of 0.48. The subsequent mixes containing the supplementary cementing materials had constant cementitious contents with water being adjusted to achieve a flow similar to the control mix. As a result, the water : binder ratios for the HRM and silica fume mixes varied. No water-reducing admixtures were used in this Phase.

Phase 2 Results

The results of the tests for Phase 2 are presented in Table2.

The control mix had the lowest water : cementitious ratio, and the silica fume mix had the highest.

The greatest strength was achieved with 7.5% replacement with PowerPozz™.

The silica fume mix, with a relatively high water demand and w / c ratio, had strengths similar to control. For this reason, silica fume is seldom, if ever, used or recommended without superplasticizing admixtures.

Phase 2 Results & Discussion

The PowerPozz™mix showed a much lower water demandthan those produced with silica fume. If this effect is compensated for by employing superplasticizing admixtures, as in Phase 1, the silica fume can produce somewhat higher strengths, but with a much higher dosage of superplasticizer.

Products produced with PowerPozz™or other metakaolins are significantly lighter in colorthan those produced with silica fume at normal addition rates.

The 28-day compressive strengthof the mortar containing 7.5% PowerPozz™, with no superplasticizers, at a 0.40 water : cement ratio exceeded all samplestested in Phase 1.

At 7.5% replacement, the PowerPozz™mortar was 9.6% higher in compressive strength than other metakaolin samples, and was 13.6% higher than the silica fume and control mortars.

PHASE 3

In this phase, the compressive strength of a plain cement mortar was compared with the strength gain of a mortar in which 10% of the cement was replaced with PowerPozzTMHRM. In this study, a dry superplasticizer was added to both the control and the test mixes, and all were produced at a water / binder ratio of 0.40 and a sand / binder ratio of 2.75. Compressive strengths presented are the averages for 3 cubes at each of the 4 age intervals (1,3,7,28 days).

Phase 3 -Results & Discussion

It is noteworthy that even with a 10% replacement of cement by 1:1 substitution of pozzolan (metakaolin) the early strengths(1,3 Days) demonstrated a positive (>1) index over control. This is indicative of the early reactivity of PowerPozzTMHRM. The early age pozzolanic reactivity and strength performance is a unique and defining feature of metakaolin, as compared to other pozzolanic materials.

It is also apparent from these results that HRM continues to indicate increasing pozzolanic reactivity at an increasing rate within the 28-day period of study. It would be normal to expect that the strength gain differential between the HRM test mix and the plain cement control will continue to widen over the long run of time. This conclusion has been made through our own research and is well corroborated by others with regard to pozzolans in general, and also specifically where HRM and like materials are concerned.

The high pozzolanic reactivityof PowerPozzTMHRM makes it, of course, an important input ingredient for the formulation of high strength materials. In fact, when mix design options with and without HRM are examined, it is normal to find that to increase the strength of a performance concrete, it is often more efficient to utilize HRM than to increase the cement content.

For concretes within the normal designcompressive strength range, the performance advantages of HRM may also be important (i.e.: low permeability, high chemical resistivity, corrosion mitigation, control of efflorescence or ASR, etc.). In these mix designs, it may be possible to use HRM as asubstitute for cement, for example at a 10% wt cement replacement level, and also reduce the total cementitious content of the mix and still met the design strength requirements comfortably.

These figures and examples are presented for illustrative and descriptive purposes only. Only a properly conducted trial batch and testing program.

will determine actual performance for a particular mix design, application, or set of raw materials.

Ask your ACT representative for assistance in the development of mix designs with metakaolin.

PowerPozz™is a mineral admixture, which offers excellent performance and can contribute to the manufacture of high strength, high durability mortars, concretes and related portland cement-based products.

All information, while provided in good faith, with every effort made to assure accuracy, is provided by Advanced Cement Technologies at no charge, and with warranty–express or implied. Data given, unless otherwise stated, are based on standard testing procedures which are available on request. Variations do occur in individual tests and the results stated herein cannot be taken for minima or maxima for specification purposes.

As we cannot anticipate all possible applications of our product, nor variations in manufacturing equipment, formulae, methods, or practices, we guarantee only that the product will meet the specifications of Advanced Cement Technologies at the time of sale. Advanced Cement Technologies reserves the right to change specifications should it becomenecessary. The product is sold without express or implied warranty, with all warranties of fitness of purpose and merchantability being disclaimed, and on condition that the purchaser is responsible for the determination of the product’s suitability for a particular purpose.

Statements concerning the possible use of our product are not intended as recommendations for use. No liability is accepted for any infringements of any existing or future patents.

All products sold, unless otherwise stated, will besubject to general sales conditions, which are supplied with all quotations and order confirmations.

10.108 – APPLICATIONS AND BENEFITS

PowerPozz High Reactivity Metakaolin has been successfully incorporated into applications for concrete and related products throughout North America and the international marketplace. The following sections will describe many of those applications and the benefits that were achieved through the use of PowerPozz.

Federal and State DOT Infrastructure Projects

Meets Engineering Specifications for High Performance, High Strength, and Lightweight Concrete.

• Bridges (structural and non structural components)
• Pavement Overlays
• Water Supply and Marine

Benefits

• Reduced Permeability
• Increased Strength and Durability
•  Prevention of ASR

Precast and Repetitive Concrete Products

• Precast
• Cast Stone
• Block, Brick, and Paving Stones

Benefits

• Increased Strength and Durability
• Reduced Permeability and Efflorescence
• Improved color and Appearance

Fibercement Products, Ferrocement, and Glass Fiber Reinforced Concret

• Roofing Products

Benefits

• Reduced Drying Shrinkage
•  Reduced Overall Permeability
• Improved Strength and Toughness

Dry Bagged Products

• Mortars
•  Stuccos
•  Repair Materials
•  Pool Plaster

Benefits

• Reduced Permeability and Efflorescence
• Improved Finishability, Color and Appearance

Specialty Uses

• Blended Cements
• Oil Well Cementing
• Shotcrete
• Decorative Interior Concrete Fixtures
• Sculpture

PowerPozz High Reactivity Metakaolin has proven itself to be a highly versatile and effective concrete additive. It has been, and will continue to be, an important component in the modern world of construction. Companies and researchers around the world are now looking at new and innovative uses for this material. We can’t wait to see where it will take us next.

10.101 -GENERAL USE
High Reactivity Metakaolin (HRM)
Engineered Mineral Admixture For Use With Portland Cement

USE PowerPozz™ in:

• High Performance, High Strengthand Lightweightconcrete
• Precast Concrete for Architectural, Civil, Industrial, and Structural
• Fibercementand Ferrocement products, Glass Fiber Reinforced Concrete
• Mortars, Stuccos, Repair Material, Pool Plasters
• Manufactured Repetitive Concrete Products

USE PowerPozz™for:

• Increased Compressive & Flexural Strengths
• Reduced Permeability & Efflorescence
• Increased Resistance to Chemical Attack& Prevention of ASR
• Reduced Shrinkage
• Improved Finishability, Color& Appearance

USING PowerPozz™:

PowerPozz™ should be used in terms of total cement weight at 5-15% loading rate. Tests have shown that for optimum pozzolanic reactivity with Ca(OH2), an 8% replacement is efficient. For prevention of ASR or efflorescence, as well as for enhanced durability in GFRC, higher loading rates, up to 15% by weight of cement may prove to be most effective.

In terms of concrete works, as always, good production and construction practices must be observed. Most importantly the water/cement ratio must be controlled. When using PowerPozz™in concrete, the use of superplasticizers, entrained air, and/or fly ash is recommended to help increase and maintain placement slumps without increasing the water content. Ask your ACT representative for assistance in testing and optimizing your formulation.

CEMENT REPLACEMENT / ADDITION

PowerPozz™substituted directly for or added to OPC at 5 -15% by weight will:

• Greatly reduce porosity and permeability
• Increase early (1-28 day) compressive strengths
• Improve late (56+ day) strengths
• Provide long term durability where ASR is a concern
• Reduce occurrence of efflorescence
• Provide enhanced resistance to chemical attack (sulfates, chlorides, acids).

POZZOLANIC SUBSTITUTION

If you are already using a high performing pozzolan in your production (i.e. silica fume/microsilica) PowerPozz™can be substituted directly. In terms of compressive strength, a reduction of the addition rate of PowerPozz™may be possible for equivalent performance. Testing with specific cements, aggregates, admixtures, etc., is strongly recommended to confirm appropriate proportioning. Further, the potential to reduce the dosage of superplasticizer required in a PowerPozz™formulation from that of a comparable silica fume mix is possible.

Substituting PowerPozz™for silica fume in existing formulationswill:

• Maintain or increase compressive strengths at early ages (1-28 days),
• Maintain long term compressive strength development (>28 days),
• Disperse more easily in the mixer with less dust,
• Not darken the color of the paste or mortar, and
• Reduce superplasticizer demand for the target slump.

PowerPozz™is compatible with chemical admixtures, as well as with other pozzolans and supplementary cementing materials, i.e.: fly ash, ground granulated blast furnace slag.

METAKAOLIN DESCRIPTION
High Reactivity Metakaolin (HRM)
Engineered Mineral Admixture for Use with Portland Cement

Advanced Cement Technologies’ PowerPozz™ High Reactivity Metakaolin is a manufactured pozzolanic mineral admixture, which significantly enhances many performance characteristics of cement-based mortars, concretes and related products.

PowerPozz™, derived from purified kaolin clay, is a white, amorphous, alumino-silicate, which reacts aggressively with calcium hydroxide, a normal cement hydration byproduct, to form compounds with cementitious value.

Produced to ISO 9002 certification standards, PowerPozz™ HRM is subjected to strict process quality control to assure product uniformity and consistent performance.

Used at 5 – 15% replacement of cement by weight, PowerPozz™ will contribute to: increased strength; reduced permeability; greater durability; effective control of efflorescence; and control of degradation caused by Alkali-Silica Reaction (ASR).

Raw Materials

The raw material input in the manufacture of metakaolin is kaolin clay.

Kaolin is a fine, white, clay mineral that has been traditionally used in the manufacture of porcelain. It is thought that the term kaolin is derived from the Chinese Kaoling, which translates loosely to white hill and has been related to the name of a mountain in China that yielded the first kaolins that were sent to Europe.

Kaolinite is the mineralogical term that is applicable to kaolin clays. Kaolinite is defined as a common mineral, hydrated aluminum disilicate, Al2Si2O5(OH)4, the most common constituent of kaolin.

Kaolins are a classification of clay minerals, which like all clays, are phyllosilicates, i.e.: a layer silicate material. The study of the stacked arrangement and the individual layers in the stack are the defining factors of classification.

Kaolin is a mineral typical of continental weathering where solutions percolate and are purified over time. Kaolinite cannot develop in sedimentary basins where solutions accumulate and are enriched.

Kaolin is one of the more highly prized of the industri al mineral clays. Kaolin’s traditional markets in ceramics over the past centuries have yielded to the now dominant consumption by the paper industry where it is extensively used as a filler, opacifier, and as an important input to high-end coatings. Additional, smaller markets for kaolin are in the refractory, rubber, paint, plastic, chemical, pharmaceutical and ceramic industries.

Metakaolin

The meta prefix in the term is used to denote change. It is a borrowing from Greek meaning after, along with, beyond. It is used, and is recognizable, in the formation of compound words: metabolic, metamorphosis. The scientific use of the prefix is used for a combining form denoting the least hydrated of a series.

In the case of metakaolin, the change that is taking place is dehydroxylization, brought on by the application of heat over a defined period of time.

At about 100-200 degrees C, clay minerals lose most of their adsorbed water. The temperature at which kaolinite loses water by dehydroxilization is in the range of 500-800 degrees C. This thermal activation of a mineral is also referred to as calcining. Beyond the temperature of dehydroxylization, kaolinite retains two-dimensional order in the crystal structure and the product is termed metakaolin.

The key in producing metakaolin for use as a supplementary cementing material, or pozzolan is to achieve as near to complete dehydroxilization as possible without over heating. Successful processing results in a disordered, amorphous state, which is highly pozzolanic. Thermal exposure beyond a defined point will result in sintering and the formation of mullite, which is dead burnt and not reactive. In other words, kaolinite, to be optimally altered to a metakaolin state, requires that it is thoroughly roasted but never burnt.

New Age Concrete

The construction industry has taken considerable strides forward over the last two or three decades with regard to many materials, in particular – High Strength Concrete (HSC) and generally Higher Performing Concrete Materials.

The development of new technology in the materials sciences is progressing rapidly. Advanced composite construction materials and HSC are gaining wide acceptance in the construction industry of today, and are well positioned for increasing proliferation in use in the future. HSC and High Performance Cement-Based Products will continue to make important contributions to the enhanced quality and efficiency in the construction of infrastructure and our communities in the next century.

PowerPozz™ High Reactivity Metakaolin

The use of pozzolanic materials in the manufacture of concrete has a long, successful history. In fact, their use pre-dates the invention of modern day portland cement by almost 2,000 years.

Today, most concrete producers worldwide recognize the value of pozzolanic enhancements to their products and, where they are available, they are becoming a basic, even a routine, concrete ingredient.

Most pozzolans used in the world today are byproducts from other industries, such as coal fly ash, blast furnace slag, rice hull ash, or silica fume. As such, there has been relatively little work done with regard to manufactured, optimized and engineered pozzolanic materials which are specifically intended for use in portland cement-based formulations. PowerPozz™ High Reactivity Metakaolin is a leader among a new generation of such materials.

The use of silica fume and various chemical admixtures have become staple ingredients in the production of concretes with designed strengths in excess of 7500 psi (>50 Mpa) or where service environments, exposure conditions, or life cycle cost considerations dictate the use of High Performance Concrete (HPC).

The introduction of High Reactivity Metakaolin to the HSC market has provided an alternative to the use of silica fume. Equivalence in strength development and durability properties along with several additional features of HRM including color and workability have effectively expanded the design boundaries of HPC materials.

The benefits in engineering properties that result from the use of PowerPozz™ HRM come with few “side effects”. Once properly adjusted, the concrete fresh mix texture, workability and finishability are generally enhanced by the replacement of 5-15% of cement with HRM.

PowerPozz™ is white in color and will not darken pigmented, gray or white cement-based concrete or products. Easy to handle in trucks, silos and plants,

 

10.150 – PHYSICAL & CHEMICAL PROPERTIES
GRADE – WHITE
High Reactivity Metakaolin (HRM)

Advanced Cement Technologies’ PowerPozz™ HRM is a manufactured pozzolanic mineral admixture which significantly enhances many performance characteristics of cement-based
mortars, concretes and related products.

PowerPozz™, derived from purified kaolin clay, is a white, amorphous, alumino-silicate which reacts aggressively with calcium hydroxide to form compounds with cementitious value.

Used at 5-15% replacement of cement by weight, PowerPozz™ will contribute to: increased strength, reduced permeability, greater durability and effective control of efflorescence and
degradations caused by alkali-silica reaction (ASR) in concrete.

Description:
A white, manufactured, amorphous alumino-silicate with excellent physical, chemical and pozzolanic properties. Conforms to ASTM C-618, Class N Specifications for Natural and Calcined Pozzolans.

All information, while provided in good faith, with every effort made to assure accuracy, is provided by Advanced Cement Technologies at no charge and without warranty–express or implied. Data given, unless otherwise stated, are based on standard testing procedures, which are available upon request. Variations do occur in individual tests, and the results stated herein cannot be taken as minima or maxima for specification purposes.