Problems discovered with Central Park fountain concrete

    The city of Washington may be in store for another downtown improvement project, but one that city officials thought was already completed. City Engineer Rob McDonald said that he and other engineers have noticed something isn?t quite right with the concrete that was poured around the Central Park fountain in the spring of 2008.

    McDonald said that tiny bits of rock called ?pea gravel? have been coming off the surface of the concrete. He said that he started receiving complaints about the pea gravel this spring after the snow and ice had melted away.

    Robert Kiefer, the city?s engineering technician, said that the type of concrete used around the fountain is known as ?exposed aggregate? because the aggregate ? the rock or sand to which the cement adheres ? is exposed on the surface of the concrete.

    Kiefer said he didn?t have much experience with exposed aggregate but commented that it was the first time he had ever seen pea gravel come off the way it has around the fountain. Neither he nor McDonald knew why the pea gravel is coming off.

    McDonald said that the north section of the concrete has been the hardest hit and that roughly three-quarters of the concrete is missing pea gravel. He said the southeast corner looks fine and does not appear to be missing much pea gravel.