There shall be a substitution in the concrete mixture of lightweight aggregate sand (LWAS) for natural and manufactured sand.  The LWAS substitution is to be on an equal volumetric basis and in accordance with the following:

• shall be expanded shale meeting ASTM C330 for Structural Lightweight Aggregate, shall meet ASTM C33 except for gradation,
• shall meet ASTM C109C, 109M for mortar strength test,
• shall be capable of having an absorption of a minimum of 15% at 24 hours and a minimum of 10% in 30 minutes, when tested in accordance with ASTM C128 for specific gravity and absorption of fine aggregate, and
• shall, when incorporated in the concrete mixture, be saturated-surface-dry (SSD) in accordance with ASTM C70.

Lightweight aggregate sand shall be shipped to the batching plant at SSD and be sprinkled while in storage for 24 hours to maintain a 24 hour absorption of a minimum of 15%.

An approximation is: 200 pounds of LWAS for a w/c ratio of 0.395.  Tests with the actual normal weight aggregates shall be used, following which the suggested 200 pounds replacement of the natural sand with lightweight sand may be modified.