Patents by Inventor Lawrence Reeder Roberts

Lawrence Reeder Roberts has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 5840114
    Abstract: A high early strength admixture for precast hydraulic cement comprises a calcium salt and a copolymer having a carbon-containing backbone to which are attached cement-anchoring members, such as carboxyl groups, and to which are also attached oxyalkylene pendant groups by linkages selected from the group consisting of amide and imide members. The copolymers used are preferably formed by reacting an acrylic polymer with ammonia or an alkoxylated amine. The calcium salt, preferably calcium nitrite, and the copolymer can be added simultaneously as one admixture, or separately. The invention relates also to methods for enhancing high early strength in concrete, cement, masonry, and mortar mixtures generally, and to precast concrete particarly, and also pertains to such hydraulic mixtures containing the calcium salt and copolymer.
    Type: Grant
    Filed: May 17, 1996
    Date of Patent: November 24, 1998
    Assignee: W. R. Grace & Co.-Conn.
    Inventors: Ara Avedis Jeknavorian, Ahmad Arfaei, Neal Steven Berke, David Charles Darwin, Ellis Martin Gartner, Leslie Ann Jardine, James Franklin Lambert, Lawrence Reeder Roberts