Document Archives

Fire Endurance of Concrete Masonry Walls with Blended Aggregates

• ID:

  57

• ESCSI:

  3220.016

• Author:

  Gustaferro

• Publication Name:

  Preliminary Paper

• Type of Publication:

  Paper

• Publisher:

  Nat. Concrete Masonry Association

• Dated:

  1960

• Issue/Volume:

  After 1960

• Other ID:

• Page(s):

  1-26

• Reference List:

  Y

• Abstract:

  Concrete masonry units are often made with “blended” aggregates, i.e., a combination of two different aggregates such as lightweight coarse aggregates and normal weight fine aggregates. For many years, building codes have tabulated fire resistance ratings to walls made of concrete masonry units based on equivalent thickness and aggregate type. However, the types of aggregates did not include blended aggregates so there has been a need for information on fire endurance of walls made with blended aggregates. A limited number of fire tests have been performed on specimens made with blended aggregates. The purpose of this study is to analyze available test data to determine if some general relationships can be established for estimating the fire endurance of concrete masonry walls made with blended aggregates. If such relationships cannot be established because of a lack of data, it may be possible to outline a test program to provide the data needed.Fire tests conducted many years ago of walls made with masonry units indicated that block made with siliceous aggregates behaved poorly in fires. More recent tests have shown that block with highly siliceous aggregates behave well in fires. Because of the poor behavior in early tests, a question arises about the effect of replacing lightweight aggregates with siliceous sand. The secondary purpose of this study is to analyze available data to determine if the use of siliceous aggregate as a replacement for some of the lightweight aggregate affects the fire endurance detrimentally.