The Methylene Blue Value (MBV) of fine aggregate is a measure of the amount of potentially harmful fine material present such as clay and organic material. Material passing the No.200 (75?m) sieve is maintained in dispersion with distilled water by mixing with a magnetic stirrer. Methylene Blue solution is titrated into the stirred dispersion in increments until a drop of the mixture on filter paper shows a blue ring indicating that the sample can absorb no more reagent. The MBV is simply a measure of the amount of reagent absorbed, and is proportional to the amount of clay or organic material present.
Methylene Blue Reagent solution is light sensitive. The solution shelf life is 4—6 months maximum, when stored in a dark cabinet in foil-wrapped amber bottles. The HM-58 Set includes 25g of methylene blue reagent in stable powder form, a 50 x 0.1ml special amber glass buret, a buret clamp and stand, two amber 500ml solution storage bottles, three glass 600ml beakers, two glass dropping rods, a 1L volumetric flask, and a 100 sheet pack of 24cm diameter filter paper. Instructions for preparation and storage of solution are provided along with details of the test procedure. The 25g of powder reagent provided in the HM-58 Set is sufficient to prepare solution for over 500 tests. Other required accessories should be ordered if not available in the lab.
Meets Test Methods:
AASHTO T 330