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Hakkinen (1986) studied the properties of alkaliactivated slag concrete and found that the expansion of AAS increased as the alkali content increased from % to % for an opal content of 8%. But when the amount of alkali was about 2% by mass of slag (typical alkali content for this kind of concrete), the measured expansion was not higher than in OPC.
Slag cement does not contain carbon and therefore should not cause fluctuations in air content. Slag cement is also compatible with pozzolans such as fly ash or silica fume. The percentage of slag cement to use for maximum strength development is usually between 40 and 50 percent.
o Air contents decrease as water to cementitious ratios are decreased. Less mix water means less air content. o Slump Air contents normally increase as slumps increase up to approximately 6. Air contents usually go up approximately %. for each inch of slump gain. Air contents normally increase as water contents are increased.
the air content will be 5 #177; 1 percent. If further reduction in the air content or the use of nonairentrained concrete is necessary, prior approval will be obtained from HQDA (DAENECEG), Washington, DC or the appropriate Air Force major command. e. Cement content. Either the contractor or the contracting officer may be
Most nonairentrained concrete contains between 1% and 2% entrapped air, and other admixtures may unintentionally entrain even more air. ACI 30116 Specifications for Structural Concrete and ACI Guide to Concrete Floor and Slab Construction indicate that air contents higher than 3% may require extra effort when finishing some mixes, leading to surface defects and delamination.
The air content of the concrete in the mixer drum may increase when the mixer load size is three cubic yards or less while air content may decrease in larger load blast furnace slag (GGBF) quantities. 11208 Decimal Drive, Louisville, Kentucky 40299, #183;
Slag cement, or ground granulated blast furnace slag (GGBFS), has been incorporated into concrete projects in the for over a century to improve durability and reduce life cycle costs. Among its measurable benefits in concrete are better workability and finishability, higher compressive and flexural strengths, and improved resistance to aggressive chemicals.
Air content Shall be entrained for Exposure Class F1, F2, F3. Concrete for hard troweled slabs shall not exceed % total air. Temperature Minimum If 3 day average less than 40 degrees, concrete 40 to 55 degrees depending on concrete dimensions. Maximum Unless otherwise specified, 95 degrees.
#0183;#32;This guide will teach you how to test air content of concrete with a type B pressure meter. It covers the reasons you are performing this test, the equipment needed, and the procedure of ASTM C231. It is intended to be a supplement to reading the ASTM as well as a study tool for the ACI exam.
Air Content Control. Measurement of air content is an important checking sensor for the concrete user to know whether concrete will resist freezethaw damage. Because average void spacing decreases as air content increases, an optimum air content at which void spacing will prevent the development of excessive pressure due to
Ordering info 64C0171 Air content meter, 1 liter capacity, to EN 4592 64C0171/A Air content meter, liter capacity, to EN 4132
Slag cement is normally used in proportions from 25 to 50 percent in structural and general concrete applications; the higher the amount of slag, the lighter the concrete. Slag cement concrete may experience some initial quot;greeningquot; after placement but this temporary color change will disappear with exposure to light and air (see related FAQ on greening and SCIC #10, quot;Greeningquot;).
Slag cement does not contain carbon and does not cause instability in the entrained air content. Time of Set. Time of initial set is influenced by the use of slag cement and fly ash. Concrete made with slag cement can have faster set times than concrete made with
Slag cement replaces as much as 50 percent in normal concrete (and up to 80 percent in special applications such as mass concrete). Fly ash is usually limited to 20 or 30 percent. Slag cement is the coproduct of a controlled process, iron production, which results in a
concrete is not anBcipated to become saturated before freezing. Even though concrete in this exposure class is not expected to become saturated, a minimum entrained air content of to 6 percent is required to reduce the potenBal for damage in case porBons of the concrete member become saturated. F2
It is not suitable to use this method when testing for air content of lightweight aggregate concrete or concrete made with air cooled blast furnace slag. For these materials, ASTM C173 is to be used. Also, ASTM C231 is not applicable for concretes often referred to as dry cast.
#0183;#32;The weight ratio between the two silica sands (F75 and F12) was and the design air content was %. The mix volume was maintained constant by adjusting the weight of silica sands. The water content was corrected by including the water contained
This test method covers the determination of the air content of freshly mixed concrete. The test determines the air content of freshly mixed concrete exclusive of any air that may exist inside voids within aggregate particles. For this reason, it is applicable to concrete made with relatively dense aggregate particles and requires determination of the aggregate correction factor (see
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