The presence of organic matter and certain chemicals can have a considerable influence on the strength and durability of concrete. The ability of aggregates to resist excessive changes in volume due to physical changees in the environment is also of importance. Knowledge of these potentially harmful factors will ensure that precautions can be taken at the mix design stage of a project.

Quantab chloride titrators can be used for estimating the chloride content of aqueous solutions. They are suitable for site testing and quality control of aggregates requiring less than 30 minutes to obtain a result.

Model No. Range
42-2950 30 - 600
42-2952 300 - 6000

If aggregate contains organic impurities it may not be suitable for inclusion in concrete. Organic impurities, usually tannic acid and its derivatives, may interfere with the chemical reactions of hydration. Impurities are more likely to be found in fine (sand) aggregate.

Model No. Desc
42-3040 Colour Standard
42-3000 Glass Bottle

The soundness of aggregates to physical changes caused by the environment is important to the long-term durability characteristics of concrete. Excessive changes in volume can be caused by freezing and thawing, thermal changes at temperatures greater than freezing, and cycles of wetting and drying. Hydrometers and Wire Baskets see Laboratory Equipment Section.

Model No. Desc
81-4819 Wire Basket - 150 μm wire mesh
81-4821 Wire Basket - 600 μm wire mesh
81-4823 Wire Basket - 1.18 mm wire mesh
81-4825 Wire Basket - 3.35 mm wire mesh
82-3505 Hydrometer used with sodium sulphate method
82-3510 Hydrometer used with magnesium sulphate method

A qualitative or semi-quantitative test is recommended for determining sulphate ions in aqueous solutions. Sulphate test strips are convenient measuring devices for preliminary assessment of sulphate content.

Model No. Desc
42-2958 Sulphate Test Strips