Date of Award

Spring 1989

Project Type


Program or Major


Degree Name

Doctor of Philosophy


Coal fly ash produced at the Merrimack Power Station, Bow, New Hampshire was tested for chemical and physical properties. Concretes made with these fly ashes were tested for their plastic and hardened properties and compared to ordinary portland cement concrete.

An experimental test burn substituting coal with Refuse-Derived-Fuel(RDF) consisting mainly of waste paper and plastic with heating value of 6000 to 8000 BTU/lb. was done by Public Service of New Hampshire at the Merrimack Power Station. Five percent and ten percent RDF was substituted, on a BTU basis, for coal in the test burns. Twelve (12) test burn days were run with 4 days of 5 percent RDF and 8 days of 10 percent RDF. The effect of RDF on the chemical and physical properties of fly ash and the effect of coal-RDF fly ash on the properties of plastic and hardened concrete were investigated.

Coal fly ash from Merrimack Power Station was classified as an ASTM class F complying to the chemical and physical properties of ASTM C-618 specifications. Coal-RDF fly ash produced during the test burn showed chemical and physical properties comparable to coal fly ash. The average chemical and physical properties of coal-RDF fly ash complied to ASTM C-618 specifications. Concrete made with coal fly ash and coal-RDF fly ash showed increased slump in high paste mixes and decreased slump in low paste mixes. Air content decreased with increased fly ash at a constant dosage of air entrainment. Compressive strength of fly ash concrete at and beyond 28 days were comparable to ordinary portland cement concrete.

Heavy metals were not leached from coal fly ash and coal-RDF fly ash concrete during a column test using a synthetic acid rain of pH 4.5 even though small quantities of cadmium and lead were found to leach from coal fly ash and coal-RDF fly ash during the beginning of the test. The volume of the acid rain was approximately equivalent to 7 years of precipitation, assuming 36 inches of rain per year. A microscopic investigation comparing the structure of pastes made with coal fly ash, coal-RDF fly ash, incinerator fly ash and incinerator bottom ash was conducted.