This paper investigates if the ASTM C1399-02 procedure minimizes the post-peak instability, and if it is able to measure the fiber-reinforced beam response at low displacements. The load and mid-span displacement curve, the crackmouth opening displacement and mid-span displacement curve and the average residual strength obtained from ASTM C1399-02 test results were compared with those obtained from ASTM C1018-94b, both conducted in an servo-controlled test machine. The results from ASTM C1399-02 were similar to those obtained according to ASTM C1018-94b. Additionally, the neutral axis value and the crack-mouth opening displacement obtained from ASTM C1399-02 were similar to those determined by ASTM C1018-94b, showing that ASTM C1399-02 test procedure did not minimize the effect of post-peak instability.

Durability is one of the key factors considered in the specification of concrete for most of its applications. When applied to industrial floors, road pavements, and sidewalks, abrasion wearing impairs the concrete performance. This work is focused on the abrasion resistance of lightweight concrete produced with expanded clay, comparing it to the performance of a conventional concrete produced with normal-weight aggregates, and with mixture proportion for an estimated compressive strength of 30 Mpa. The lightweight aggregate structure was investigated through mercury intrusion porosimetry and water absorption tests. The parameters used to evaluate the abrasion phenomena were thickness and mass loss of the concretes, which resulted from the friction between the specimens and an abrasive material. Although the expanded clay presents lower abrasion resistance than the normal-weight aggregate, due to its higher porosity; for example, both concretes behaved similarly regarding their wearing resistance. The denser interfacial transition zone between the expanded clay and the cement paste in the lightweight concrete seems to compensate for the lower wear resistance of the aggregate.

This ACI Special Publication (ACI SP-253) CD-ROM contains 25 papers from the Fifth ACI/CANMET/IBRACON International Conference on High-Performance Concrete Structures and Materials that was held in Manaus, Amazon State (AM), Brazil, June 18-20, 2008. Topics include Durability, Self-Compactability, Curing, Retarders, and Abrasion Resistance. The Fifth Conference is a result of the collaboration of ACI and CANMET along with Sao Paulo University, Federal University of Goias, Amazon State University, and Brazilian Concrete Institute (IBRACON).

This paper presents a review of the application of concrete to offshore structures in the last 35 years. The state-of-the-art technology available for offshore oil platforms and other offshore applications is also described. Currently, there are around 350 offshore gravity and floating concrete platforms in operation in the North Sea, Northern Canada, Australia, Netherlands, Congo, Nigeria, Indonesia, Russia, the Philippines, Brazil, and the Gulf of Mexico. More recently, an important LNG offshore terminal has been designed and is now under construction in Algeciras, near the Gibraltar Strait in Spain. Over the past 30 years there has been a considerable improvement in the design and construction aspects of concrete production. Water-reducing admixtures and additions, such as metakaolin and silica, allowed the development of concretes with improved performance. These new concretes can easily achieve much higher strengths and durability which make them much more suitable for offshore applications. The liberal use of lightweight aggregates is considered crucial for a total weight reduction of the structure and for floating considerations. The evolving technology for the design and construction of this type of structures is discussed.

Steam curing at atmospheric pressure is an important technique for obtaining high early strength values in precast concrete production. The aim of this work was to explore the potential benefits of steam curing in concrete products made with different cements types and with supplementary cementitious materials. All concretes mixtures had the same workability and were produced with two cements both with and without silica fume replacement (10% by mass): highearly-strength portland cement and blast-furnace slag portland cement. For each mixture, specimens were subjected to three curing conditions. Immersion curing until the age of 7 days, curing in air and steam curing at temperatures of 60°C and 80°C maximum temperature over 4 h. Concretes were prepared and tested for initial surface absorption and air permeability. Compressive strength was also determined. The concretes were tested at different ages: 1, 3, 7, 28, 90, and 180 days. The results showed that the concretes with silica fume presented a lower air permeability and capillary absorption, mainly in later ages, when compared with concretes without silica fume for all curing procedures and both portland cements used. The inclusion of silica fume improved performance of concrete produced with blast-furnace slag portland cement at temperature of 80°C. High-early-strength portland cement had a good performance with silica fume replacement. The curing method adopted had significant effects on the near-surface properties of concrete incorporating silica fume.