Joseph Richard Allen

US Patent:

40024830, Jan 11, 1977

Filed:

Jun 12, 1975

Appl. No.:

5/586225

Inventors:

Kenneth E. Daugherty - Lewisville TX
John P. Luker - Comanche TX
Joseph H. Allen - Irving TX
Waldemar A. Klemm - Columbia MD

Assignee:

General Portland, Inc. - Dallas TX

International Classification:

C04B 702

US Classification:

106 89

Abstract:

An improved expansive cement composition is provided which has the increased capability of being able to " grab" steel reinforcement members therewithin as the material is curing and expanding to result in effective stressing of the reinforcement members. This cement is made of particulate argillaceous and calcareous materials, and contains from about 1 to about 70% by weight of free CaO and from about 2 to about 7% by weight of MgO uniformly distributed therein, with the remaining portion being primarily tricalcium silicate and containing substantially no dicalcium silicate. The improved expansive composition can be manufactured by subjecting a conventional Portland cement raw mix, which has been "overlimed" and which contains the added quantity of MgO, to hard burning conditions within a Portland cement kiln such that the silicate materials are reacted with lime to form tricalcium silicate but yet leave from about 1 to about 70% by weight of the free CaO, and from about 2 to about 7% by weight of the MgO in the clinker, and thereafter comminuting the clinker. The composition can be used directly as an expansive cement, or can be mixed with other cements such as Portland cements to impart expansive qualities thereto.