Henry A. Lepper Jr., 70, a professor emeritus of civil engineering at the University of Maryland and an authority on poured concrete and structural engineering, died of cancer April 3 at Suburban Hospital.

Dr. Lepper, a resident of Silver Spring, was born in Washington. He graduated from McKinley Technical High School and George Washington University. He earned a master's degree at the University of Illinois and was an instructor there and then went to Yale University, where he received a doctorate in civil engineering in 1947.

He taught at Yale until 1958 and from 1956 to 1958 also was acting head of the department of civil engineering. He then joined the faculty of the University of Maryland. He retired in 1980 and was appointed a professor emeritus in 1981.

Dr. Lepper was a former president of the Maryland and Yale chapters of Sigma Xi, an honorary scientific organization, and a member of Tau Beta Pi, an honorary engineering society. He was a fellow of the American Society of Civil Engineers and a member of the American Society of Testing Materials. In the latter organization he served on several committees on such issues as quality in design and materials and structural safety in poured concrete.

Dr. Lepper also was a member of the College Park Rotary Club and chairman of its student affairs committee. He was made a Paul Harris Fellow of Rotary International for his contributions to the organization's international student exchange program.

Survivors include his wife, Dorothy Russell Lepper of Silver Spring, and one brother, Dr. Mark H. Lepper of Chicago.