FIELD ADJUSTMENT FOR CONCRETE MIXES IN ACCORDANCE WITH MOISTURE CONDITIONS OF AGGREGATES

Hussain Ali, Ali; Sadi Hassan, Nadwa; Yasin Hammed, Mohammed

	FIELD ADJUSTMENT FOR CONCRETE MIXES IN ACCORDANCE WITH MOISTURE CONDITIONS OF AGGREGATES
AL-TAQANI
Article 1, Volume 24, Issue 8, 2011, Pages 0-0
Authors
Ali hussain Ali; Nadwa Sadi Hassan; Mohammed Yasin Hammed
Abstract
American Concrete Institute (ACI) mix design method, was used to calculate the quantities of the constituents (cement, water, sand, and gravel) of a specific Non-air-entrained concrete of a specified workability and compressive strength. These quantities are calculated on the basis that the aggregates were in the saturated-surface dry (S.S.D.) condition. Aggregates in the S.S.D. condition can be prepared and controlled in the laboratory, but in the field, it is difficult and impossible to gain it. Therefore, nine probabilities of moisture conditions of the aggregates will be arise in the site works (at the mixer), and, in order to overcome this problems, field adjustment with relation to moisture condition of aggregates must be done when the concrete compounds were put in the mixer. Experimental work shows that, the 7 and 28 days compressive strengths are (27.10) and (38.74) MPa respectively using the mix proportions of the reference mix designed by the ACI method and the S.S.D. aggregates. Good results (an average value of 35.80 MPa) are obtained using the nine probable cases of moisture condition other than the S.S.D. All the adjusted mix proportions can be used practically and successfully, and their values are acceptable comparing with the 28-day characteristic strength (34.00) MPa of the reference mix obtained using the ACI method. Finally, empirical expressions are derived to calculate the adjusted quantities of concrete constituents for the nine probable cases of moisture conditions
Keywords
Field Adjustment; Moisture Conditions; Absorption Capacity; Surface Moisture

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