Technical Questions

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Minimum Dimension of a Structure

Q. What is the minimum dimension of a structure, and how does it affect mass concrete?

 

A. The minimum dimension is the smallest of length, width, and thickness of a structure. The minimum dimension of a structure is a key factor for determining the rate of cooling (shortest path of heat escape).

Concrete structures with relatively small minimum dimensions and low cement contents are usually not considered mass concrete because the generated heat of hydration can dissipate fast enough so that not to allow temperature and temperature differentials in concrete to exceed limits.  Large minimum dimensions usually lead to the retention of generated heat in the core of the concrete; this leads to temperature differentials and thermal cracking in the cases were temperature control is not implemented.

 

References: ACI 301-20; ACI 207.1R-05; ACI 207.2R-07; ACI PRC-207.4-20

Topics in Concrete: Mass Concrete; Specifications

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