Development of Maturity Protocol for Construction of NJDOT Concrete Structures

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CAIT project no.: FHWA NJ 2001 017

Fiscal Year: 1997/1998

Status: Final

Rutgers-CAIT Author(s): Ali Maher

External Author(s): Farhad Ansari, University of Illinois at Chicago, Allyn Luke, NJITYongtao Dong, University of Illinois at Chicago Nicholas Vitillo



In-place tests can be used to estimate concrete strength during construction so that construction operations can be performed safely or curing procedures can be terminated. Compression tests pertaining to field cylinders do not represent the strength of concrete as it exists in the structure. Maturity method, when properly employed provides a good estimate of concrete strength. As with any other technique, the maturity test needs to be accompanied by other in-place tests or compressive cylinders tests to assure safety. This report summarizes a comprehensive program of research pertaining to the development of maturity protocols to facilitate in-place estimation of compressive strength for NJDOT concretes. This report is intended as a guide for NJDOT personnel for procedures and computations regarding the application of maturity method to NJDOT construction projects. Maturity parameters, i.e. the activation energy and the datum temperature for NJDOT concretes were determined through laboratory experiments. Experiments pertained to monitoring of thermal history for concrete mixtures cured under three curing temperatures. Compressive strength of these samples were determined through uniaxial compression tests. Laboratory strength-maturity-correlation relationship or a typical construction project was developed. The construction site at the intersection of I-78 and routes 1 & 9, and 21 was chosen for field studies. Thermal history of a pier-cap, a footing, and a column was recorded via electronic maturity meters. Statistical analysis of data was carried out, and a method introduced for the interpretation of maturity data.