By: Expert No. 8793, P.E.

Many investigations related to construction involve the use of concrete; and, frequently, it seems that the concrete is not performing as anticipated. Such problems often are related to cracking of the concrete, but cracking is usually only the most visible manifestation of a problem.

The adjacent figure shows crack patterns on concrete panels that are the results of field research performed in Southern California some years ago. This research showed that once concrete is placed directly on a polyethylene membrane, it will crack at a later age with almost no regard to subsequent effort to cure the concrete. This research was submitted as part of a condition survey that resulted in the settlement of a claim by the owner for remediation of the improperly installed material.

The cracking pattern that existed at 52 weeks was drawn on the three plan views. The elevation shows the subgrade and curing used on each section at the test slabs. Authorized reprint from Journal of the American Concrete Institute, 1/76, No. 1, Proceedings V. 73.Click here for enlarged diagram

If your concrete problem needs a similar or more thorough diagnosis, be sure to call a civil engineer whose practice specializes in performance evaluations (sometimes called condition surveys) of concrete. This specialist can tell if the cracking is a result of ordinary drying shrinkage, reactive aggregates, construction details or techniques, loading (including earthquake or other vibrations), or some other problem.

As part of the investigation, the engineer may recommend destructive or non-destructive testing. This may be done by obtaining core samples and having them tested to determine strength or examined by a petrographer who looks at the material with the aid of microscopes and other techniques and can provide extensive information that may verify many improper activities, such as inappropriate addition of water when the concrete was placed, indications of improper or no curing, deviation from the approved concrete mix designs, or evidence that the concrete cracked at a relatively early age rather than more recently. More sophisticated tests can also be specified, if appropriate.

Many recent construction defect lawsuits include a claim of chemical attack by sulfates to the site and structural concrete. The proposed repairs typically consist of full replacement of all concrete. Some research data suggest that improperly placed and designed concrete in a high sulfate environment will deteriorate within the expected life of the project. Investigation, testing and evaluation can provide useful information to investigate such claims and aid in successful settlements.

Concrete construction is a field subject to many varieties of specialization, and it is usually a great benefit to involve a specialist in the investigation of concrete-related problems.

Expert No. 8793, P.E. – A registered professional civil engineer in California with well over 30 years of experience, and specializes in concrete and concrete materials; analysis of deterioration of strength and condition; corrosion of reinforced metal and repairs to structures; preplaced aggregate concrete, epoxy injection, chemical and cementitious grouts for structural and waterproofing purposes. He brings specialized services to ForensisGroup’s clients, primarily in assessing damages to structures from typical causes; construction practices, fire, earth movement, reinforcing steel corrosion and others.

Similar experts may be found under:
Civil Engineer, Concrete, Construction Defects, Corrosion, Failure Analysis, Metals And Alloys, Waterproofing, Welding

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