Describes, with examples, methods for proportioning and adjusting proportions of structural grade concrete containing lightweight aggregates. The weight (pycnometer) method uses a specific gravity factor determined by a displacement pycnometer test on the aggregates (Method 1). The weight method also employs the specific gravity factor to estimate the weight per yard of the fresh cement. The samp, loose volume method uses the cement content-strength relationship for the design of all lightweight and sand lightweight concretes (Method 2). Examples are given for systematic calculation of batch weights, effective displaced volumes, and adjustments to compensate for changes either in aggregate moisture content, aggregate proportions, cement content, slump or air content.
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Published: 01/01/1998 Number of Pages: 18 File Size: 1 file , 510 KB