It is recommended that our Norlite customers follow a few handling and-stockpiling procedures in order to maintain the proper gradations. Cone stockpiling should always be avoided to prevent segregation. Stockpiles should be arranged so that stocking and removal operations may be conducted without having machinery rolling onto or over the inventoried aggregate. The method of removing material from a stockpile is also of importance. Handling equipment should be worked straight into the stockpile as far as practically possible. The adjacent areas may then be worked in the same manner. Stockpiles should never be worked around the edges one load at a time.
Norlite involves no great difficulties in the batching and mixing operations. This lightweight aggregate has a higher moisture absorption capability than sand and gravel stone. Because the moisture content varies more sharply with atmospheric conditions than the natural aggregates, the moisture content of the Norlite should be known at the time of mixing. This will allow the proper calculation for free water and yield. Experience has shown that Norlite in a dry condition will absorb 5% to 8% moisture within the first two or three minutes of mixing the water and lightweight aggregate as recommended below. After this initial water demand has been met, there is no appreciable absorption. For this reason saturation of the lightweight aggregate to its maximum absorption is not necessary (with the exception of pumping). The following mixing procedures are recommended:
- Charge the mixer with approximately 2/3 of the total mixing water and all of the lightweight aggregate. Allow high speed mixing for a period of 2 to 3 minutes.
- If natural sand is used it may then be added along with any air entraining agent.
- The cement and remaining water are then introduced along with any water reducing agent.