We are back! After a long hiatus, the Maryland Chapter ACI is bringing back its speaker series
and is starting off with two topics that are sure to be of interest to specifying agencies, ready
mix producers, and concrete contractors.
Petrography is the examination of concrete under a microscope, and it is often the best and
only means of determining the cause of concrete distress. Our speaker, Nick Scaglione, is not
only a great petrographer but also a brilliant speaker, taking complex subjects and explaining
them in simple terms with slides graphically illustrating the power of the microscope in
determining the causes of concrete distress.
ACI is an educational institution not a promotional one. Our chapter provides learning
opportunities for practitioners and specifiers and works closely with the Maryland DOT to
determine better means and methods of producing durable concrete. This learning
opportunity is provided FREE of charge to all Government agencies with a Coupon Code  and qualifies for Professional Development Hours (PDHs).

Part 1: Determining the cause of concrete surface destress.

10:00 am – 12 Noon

Lunch 

12:00 - 1:00 pm

Part 2: Determining the presence of destructive ASR in concrete swimming pools.

1:00 pm – 2:30 pm

Part 1

The past winter was moderately harsh both in terms of low temperatures and freezing
precipitation. It was the first real winter our area has experienced in several years. Roadways
were heavily salted, and scaling was observed in sidewalks, driveways, pavement, and bridge
decks early in 2025.
Several theories were suggested as to the cause of the scaling, ranging from problems with
concrete finishing practices to concrete material issues (namely, proper mix design and the use
of Type IL cement).
Nick Scaglione will discuss both the common types of surface distress and the physical and
petrographic means for determining the cause of these problems. He has also been involved in
much of the local, mid-Atlantic testing that has been performed and will provide feedback on
the concerns he has investigated and the conclusions he has developed.

Part 2

Akali Silica Reaction is a destructive mechanism that can occur in concrete where reactive
aggregate are present in a high alkali atmosphere (typically provided by the cement) with water
as the driving force of the reaction. It was first broadly addressed in the mid-Atlantic in the
early 1990’s and specifications have largely controlled the deleterious expansion of the reactive
aggregate since this time.
Recently, many states have identified ASR as a problem again, specifically in concrete swimming
pools. Pools are potentially problematic in the formation of ASR because they can supply a
constant source of water to fuel the ASR reaction. Further complicating the reaction is the
more recent use of salt water in swimming pools, as these salts can cause an increase in the
reactive components.
Nick Scaglione has a vast knowledge of such problems and will bring experience from the many
projects he has been involved in to provide insight into how the reaction occurs, how he
identifies it, and strategies for reducing the risk for deleterious ASR in this aggressive
environment.

Nick Scaglione is the President and Senior Petrographer for Concrete Research and Testing in
Columbus, Ohio, is an honorary member of ASTM, the Past President of the Society of Concrete
Petrographers, is a member of ACI 201 (Durability of Concrete), and has nearly 30 years of
experience in the petrographic examination of concrete. The author of several studies, he has
worked extensively throughout his career determining the mechanisms of distress in concrete
using sophisticated equipment and techniques.