Concrete Technology Updates
BASF offers a range of technical articles to help the concrete industry solve everyday challenges. Browse the following articles for information provided by the experts at BASF:
What Every Quality Control Manager Should Know About Concrete Compressive Strength Testing
When strength test results of in-place concrete are lower than expected, debate over in-place concrete quality and performance occurs between concrete producers, independent laboratories, contractors, material suppliers, and engineers. Lower than expected strength may be due to one or a combination of factors. However, mistakes in testing concrete have been known to adversely influence results. Analyzing the test procedures used should be the first action to confirm if there really is a problem. Click here for the article
Evaluation of the Causes of Efflorescence in Concrete Masonry Products and Recommended Guidelines for Efflorescence Control
In this technical report, primary and secondary efflorescence in concrete are defined and evaluated in detail. Factors contributing to efflorescence are also discussed. Although efflorescence cannot be prevented completely, it can be controlled using recommended practices and Rheopel® water-repellent admixtures. Guidelines are provided for efflorescence control methods. Click here for the article
Chlorides and Admixtures
Because chlorides exist naturally in most materials, they are likely to be present in trace amounts even in so-called nonchloride admixtures. It is shown in this publication that nonchloride-bearing admixtures with a chloride ion content of 0.5 percent by mass will contribute only a very small fraction of the total chloride ion content of most concrete mixtures. Click here for the article
Thiocyanates
It is well known in the concrete industry that thiocyanates are effective in accelerating the setting of portland cement and enhancing early strength development of concrete. In the late 1980s some concern was expressed over the use of thiocyanates in chemical admixtures. The issue of thiocyanates was given a great deal of attention by ACI Committee 212, Chemical Admixtures, and by the American Institute of Architects (AIA). This technology update presents the facts and the position adopted by the technical committees. Click here for the article
Shrinkage of Concrete
The major concern with regard to the shrinkage of concrete is the potential for cracking either in the plastic or the hardened state. In most situations, the likelihood of plastic and/or drying shrinkage is often greater than that of the other types of shrinkage. Therefore, further details on the mechanisms by which these two types of shrinkage occur and the influences of concrete mixture ingredients, ambient conditions, design and construction practices, and the methods to prevent/reduce shrinkage are presented in this article. Click here for the article
Inhibiting ASR with Lithium Admixtures
Alkali-silica reaction (ASR) is a major durability issue in many concrete structures. Lithium-based admixtures have been used since the 1950s to prevent the expansion induced by ASR. This article provides the details of ASR and the methods of mitigating it with an emphasis on lithium-based admixtures. Click here for the article
Hot and Cold Weather Concreting Both hot weather and cold weather can lead to many problems in mixing, placing, and curing of concrete that can have an adverse effect on its properties and service life.These guides have been developed by BASF to assist the entire construction team (owners, specifiers, contractors, and ready mixed concrete producers) in the design, manufacture, delivery, placement, and curing of quality concrete in hot and cold weather.