The characteristics of concrete depend on the quantities and qualities of its components. One of the most active components is cement and usually has the greatest unit cost; therefore, its selection and proper use are crucial for obtaining the most economic concrete mix and for the balance of properties desired for any particular concrete mixture.
While some types of cement can provide adequate levels of strength and durability, some other applications require the use of other cements to provide higher levels of properties; the use of blended cements with aggregates subject to alkali-aggregate reactions are examples of such applications.
Every single property of cement should be tested as it would have its particular impact on the concrete as summarized below:
Cement Property |
Impact of Concrete Properties |
Cement Contnet, fineness, etc |
Placeability and workability |
Cement composition (C3A, C3S. C2S, etc) |
Strength |
Sulfate content with Cement composition |
Drying Skrinkage |
Cement composition, fineness, presence of cementetious materials |
Durability (Permeability, Surface absorption, etc) |
C3A content |
Resistance to sulfate |
Alkali content |
Alkali Silica Reactivity |
Heat of Hydration |
Trend of strength and possibility of crack |
TQP offers a wide range of cement physical and chemical cement testing in accordance with BS, EN and ASTM standard test methods.
Cement Testing
| Cement | Test Method | Description |
|---|---|---|
| Activity index of fly ash | ASTM C311 | These test methods cover procedures for sampling and testing fly ash and raw or calcined pozzolans for use in Portland-cement concrete. It allows determining the maximum amount of fly ash that could be used in concrete without affecting its strength more than the specified %. |
| Activity index of silica fume | ASTM C311/ C1420 | The test for strength activity index is used to determine whether fly ash or natural Pozzolan results in an acceptable level of strength development when used with hydraulic cement in concrete. Since the test is performed with mortar, the results may not provide a direct correlation of how the fly ash or natural Pozzolan will contribute to strength in concrete. |
| Blending of cement/kg | TQP | TQP uses chemical and physical testing, either destructive or non-destructive, to verify the quality of your product. |
| Bond Strength by Slant Shear | ASTM C1042 | This test method covers the determination of the bond strength of latex bonding systems for use with Portland-cement concrete. This test method covers bonding hardened mortar specimens to freshly mixed mortar specimens. This test method can be used in measuring the effectiveness of latex systems in bonding fresh concrete to hardened concrete. |
| Compressive Strength of Grout cubes | ASTM C109 | This test method covers the determination of the compressive strength of hydraulic cement grout. |
| Compressive strength of grout cubes (inc mixing and curing, 6 specimens) | Data sheet | This test method covers the determination of the compressive strength of hydraulic cement grout including mixing and sampling in the laboratory. |
| Compressive Strength of Portland Cement | ASTM C109 | This test method covers determination of the compressive strength of hydraulic cement mortars, using 2-in. or [50-mm] cube specimens. This test method provides a means of determining the compressive strength of hydraulic cement and other mortars and results may be used to determine compliance with specifications. Caution must be exercised in using the results of this test method to predict the strength of concretes. |
| Density of hydraulic cement | ASTM C188 | This test method covers the determination of the density of hydraulic cement using Le Chatelier’s flask. Its particular usefulness is in connection with the design and control of concrete mixtures. |
| Drying shrinkage of mortar | ASTM C596 | This test method determines the change in length on drying of mortar bars containing hydraulic cement and graded standard sand. This test method establishes a selected set of conditions of temperature, relative humidity and rate of evaporation of the environment to which a mortar specimen of stated composition shall be subjected for a specified period of time during which its change in length is determined and designated “drying shrinkage”. The drying shrinkage of mortar as determined by this test method has a linear relation to the drying shrinkage of concrete made with the same cement and exposed to the same drying conditions. Hence this test method may be used when it is desired to develop data on the effect of a hydraulic cement on the drying shrinkage of concrete made with that cement |
| Expansion of Portland-cement mortars stored in water | ASTM C1038 | This test method covers the determination of the expansion of mortar bars made using hydraulic cement, of which sulfate is an integral part. This test method is used to determine the amount of expansion of a mortar bar when it is stored in water. The amount of mortar-bar expansion may relate to the amount of sulfate in the cement; expansion may become excessive when the cement contains too much sulfate. Some cement specifications limit the amount of sulfate contained in hydraulic cement by requiring that the amount of expansion in water not exceed a specified value. |
| Fineness of cement-Passing 45 micron | ASTM C430 | This test method covers the determination of the fineness of hydraulic cement by means of the 45-μm (No. 325) sieve. |
| Fineness of hydraulic cement-Blaine | BS EN 196-6 | This test method covers determination of the fineness of hydraulic cement, using the Blaine air-permeability apparatus, in terms of the specific surface expressed as total surface area in square centimeters per gram, or square meters per kilogram, of cement. Although the test method may be, and has been, used for the determination of the measures of fineness of various other materials, it should be understood that, in general, relative rather than absolute fineness values are obtained. This test method is known to work well for Portland cements. However, the user should exercise judgment in determining its suitability with regard to fineness measurements of cements with densities, or porosities that differ from those assigned to Standard Reference Material No. 114. The limits for the fineness of Portland cement are found in ASTM C 150. |
| Flexural Strength of Cement Mortar (ASTM) | ASTM C348 | This test method covers the determination of the flexural strength of hydraulic-cement mortars. This test method provides a means for determining the flexural strength of hydraulic cement mortars. Portions of the mortar prisms tested in flexure according to this test method may be used for the determination of compressive strength in accordance with Test Method C 349. |
| Flexural Strength of Cement Mortar (BS) | BS EN 196-1 | This test method provides a means for determining the flexural strength of hydraulic cement mortars. Portions of the mortar prisms tested in flexure according to this test method may be used for the determination of compressive strength. |
| Flexural strength of grout cubes (inc mixing and curing, 6 specimens) | Data sheet | This test method provides a means for determining the flexural strength of grout mortars including mixing and sampling in the laboratory. |
| Length change of hydraulic-cement mortars exposed to a sulfate solution | ASTM C1012 | This test method covers the determination of length change of mortar bars immersed in a sulfate solution. Mortar bars made using mortar described in Test Method C 109/C 109M are cured until they attain a compressive strength of 20.0±1.0 MPa, as measured using cubes made of the same mortar, before the bars are immersed. |
| Linear shrinkage and coefficient of thermal expansion of chemical resistant mortars, grout mortars and polymer concrete | ASTM C531 | This test method covers the measurement of the linear shrinkage during setting and curing and the coefficient of thermal expansion of chemical-resistant mortars, grouts, monolithic surfacing, and polymer concretes. A bar of square cross-section is cast to a prescribed length in a mold that holds measuring studs that are captured in the ends of the finished casting. Shrinkage determinations should not be made on sulfur mortars, since this test method cannot truly reflect the overall linear shrinkage of a sulfur mortar. The change in length after curing is measured and used to calculate shrinkage. The change in length at a specific elevated temperature is measured and used to calculate the coefficient of thermal expansion. This test method is limited to materials with aggregate size of 0.25 in. (6 mm) or less. |
| Normal Consistency of Portland cement | ASTM C 187 | This test method covers the determination of the normal consistency of hydraulic cement, which is the amount of water required to prepare hydraulic cement pastes for testing. |
| Pozzolanicity of cement | BS EN 196-5 | This test describes the method of measuring the Pozzolanicity of pozzolonic cements conforming to ENV 197-1. This standard does not apply to Portland pozzolona cements or to pozzolans. |
| Setting time of Portland cement (ASTM) | ASTM C191 | These methods determine the time of setting of hydraulic cement by means of the Vicat needle. The measured time of setting is affected by the percentage and temperature of the used water, the amount of kneading the paste received, and by the temperature and humidity of the mixing room air and the moist cabinet or moist room air. The measured time of setting of hydraulic cement is test-method specific. Time of setting as measured by this method will not necessarily be similar to other methods used for determining the time of setting of hydraulic cements. |
| Soundness of cement by Le Chatelier | EN 196-3 | This European Standard describes the methods for determining soundness of cements using Le Chatelier’s flask. It is applicable to all cements covered by ENV 197-1. |
| Chemical analysis of cement | ASTM C114, BS EN 196-2 | This test method covers the determination of the major and minor constituents of hydraulic cement. The chemical requirements of Portland cement are stated in ASTM C150. ASTM C150 specification covers eight types of Portland cement as follows: Type I-For use when the special properties specified for any other type are not required. Type IA-Air-entraining cement for the same uses as Type I, where air-entrainment is desired. Type II-For general use, more especially when moderate sulfate resistance or moderate heat of hydration is desired. Type IIA-Air-entraining cement for the same uses as Type II, where air-entrainment is desired. Type III-For use when high early strength is desired. Type IIIA-Air-entraining cement for the same use as Type III, where air-entrainment is desired. Type IV-For use when a low heat of hydration is desired. Type V-For use when high sulfate resistance is desired. |
| Chemical analysis of fly ash | ASTM C114 | Fly ash is a byproduct of the combustion ofpulverized coal in electric power generating plants. It is the most widely used supplementary cementitious material in concrete. Fly ash is of two classes Class F and Class C. The main features of Fly Ash are: Spherical Shape: Fly ash particles are almost totally spherical in shape, allowing them to flow and blend freely in mixtures. Ball Bearing Effect: The “ball bearing” effect of fly ash particles creates a lubricating action when concreteis in its plastic state. Higher Strength: Fly ash continues to combine with free lime, increasing structural strength over time. Reduced Permeability: Increased density and longterm pozzolonic action of fly ash, which ties up free lime, results in fewer bleed channels and reduces permeability. Increased Durability: Dense fly ash concrete helps to keep aggressive compounds on the surface, where destructive action is lessened. Fly ash concrete is also more resistant to attack by sulfate, mild acid, soft(lime hungry) water, and sea water. Reduced Sulfate Attack: Fly ash ties up free lime that can combine with sulfate to create destructive expansion. Reduced Efflorescence: Fly ash chemically binds free lime and salts that can create efflorescence and dense concrete holds efflorescence producing compounds on the inside. Reduced Shrinkage: The largest contributor to drying shrinkage is water content. The lubricating action of fly ash reduces water content and drying shrinkage Reduced Heat of Hydration: The pozzolonic reaction between fly ash and lime generates less heat, resulting in reduced thermal cracking when fly ash is used to replace Portland cement. Reduced Alkali Silica Reactivity: Fly ash combines with alkalis from cement that might otherwise combine with silica from aggregates, causing destructive expansion. Workability: Concrete is easier to place with less effort, responding better to vibration to fill forms more completely. Ease of Pumping: Pumping requires less energy and longer pumping distances are possible. Improved Finishing: Sharp, clear architectural definitions easier to achieve, with less worry about in place integrity. Reduced Bleeding: Fewer bleed channels reduce porosity resulting in a higher resistance to chemical attacks. Reduced Segregation: Improved cohesiveness of fly ash concrete reduces segregation that can lead to rock pockets and blemishes. Reduced Slump Loss: More dependable concrete allows for greater working time, especially in hot weather. Because fly ash is a by-product material chemical constituents can vary considerably but all fly ashes includes: Silicon Dioxide (SiO2); Calcium Oxide (CaO) also known as Lime; Iron (III) Oxide (Fe2O3); Aluminum Oxide (Al2O3).This test method covers the determination of the major constituents of fly ash. The chemical requirements of fly ash are stated in ASTM C 618. |
| Chemical analysis of gypsum (Gypsum content) | ASTM C471 | These test methods cover the chemical analysis of gypsum and gypsum products, including gypsum ready-mixed plaster, gypsum wood-fibered plaster and gypsum concrete. |
| Chemical analysis of pozzolona | ASTM C114, C311 | This test method covers the determination of the major constituents of Pozzolan. The chemical requirements of Pozzolan are stated in ASTM C 618. |
| Chemical analysis of silica fume | ASTM C114 | This test method covers the determination of the major constituents of silica fume. The chemical requirements of silica fume are stated in ASTM C 1240. |
| Chromium VI content of cement | EN 196-10 | This European Standard specifies the method for the determination of the water-soluble chromium (VI) content of cement due to its carcinogenic properties. |
| Determination of C3A in Portland cement | ASTM C114 | Tricalcium aluminate (C3A) hydrates and hardens the quickest. It liberates a large amount of heat almost immediately and contributes somewhat to early strength. Gypsum is added to Portland cement to retard C3A hydration. Without gypsum, C3A hydration would cause Portland cement to set almost immediately after adding water. |
| Heat of hydration of cement | ASTM C186 | This test method covers the determination of the heat of hydration of a hydraulic cement by measuring the heat of solution of the dry cement and the heat of solution of a separate portion of the cement that has been partially hydrated for 7 and for 28 days, the difference between these values being the heat of hydration for the respective hydrating period. The purpose of this test is to determine if the hydraulic cement under test meets the heat of hydration requirement of the applicable hydraulic cement specification. Determination of the heat of hydration of hydraulic cements provides information that is helpful for calculating temperature rise in mass concrete. |
| Insoluble residue of cement | ASTM C114 | The determination of insoluble residue of cement is an indication of the purity of the cement. It shall be below 1% for Portland cement as per ASTM C150. |
| Loss on ignition | ASTM C114/ TQP | In this test method, the cement is ignited in a muffle furnace at a controlled temperature. The loss is assumed to represent the total moisture and CO2 in the cement. This procedure is not suitable for the determination of the loss on ignition of Portland blast-furnace slag cement and of slag cement. |
| Slag content in cement | BS 1047 | The slag content in cement is determined volumetrically by chelation with ethylene diamine tetra acetic acid. |
| Potential alkali reactivity of cement-aggregate combinations (Mortar-Bar method), monthly reading | ASTM C227 | This test method covers the determination of the susceptibility of cement-aggregate combinations to expansive reactions involving hydroxyl ions associated with the alkalies (sodium and potassium) by measurement of the increase (or decrease) in length of mortar bars containing the combination during storage under prescribed conditions of test. Alkalies participating in the expansive reactions usually are derived from the cement; under some circumstances they may be derived from other constituents of the concrete or from external sources. Two types of alkali reactivity of aggregates are recognized: - an alkali-silica reaction involving certain siliceous rocks, minerals, and natural or artificial glasses and - an alkali-carbonate reaction involving dolomite in certaincalcitic dolomites and dolomitic limestone (see Standard C294). The method is not recommended as a mean to detectthe latter reaction because expansions produced in the mortarbartest by the alkali-carbonate reaction (see Test MethodC586) are generally much less than those produced by thealkali-silica reaction for combinations having equally harmfuleffects in service. |
| Potential expansion of Portland-cement mortars exposed to sulfate | ASTM C452 | This test method, which is applicable only to Portland cements, covers the determination of the expansion of mortar bars made from a mixture of Portland cement and gypsum in such proportions that the mixture has a sulfur trioxide (SO3) content of 7.0 mass %. This test method is used primarily by those interested in research on methods for determining the potential sulfate resistance of Portland cement. This test method is also used to establish that a sulfate-resisting Portland cement meets the performancerequirements of Specification C150. |
