Abstract To accelerate the curing of concrete, heat is applied to a fluid concrete mix substantially uniformily over the outer mix surface. The temperature of the mix is sensed and the application of the heat is terminated when that temperature reaches a predetermined level such that the immediately subsequent exothermic heating within the mix further increases its temperature only to a substantially predetermined maximum value that corresponds to substantially maximum subsequently ultimate compressive strength of the concrete. In one structural embodiment, an electrically energized element is disposed substantially in convective contact with a form in which the mix is received; the element produces heat substantially uniformly over the surface of the form. The heating element is de-energized when the temperature of the form reaches a preselected value. In another structural version, a frame is shaped to mount upon the upper periphery of the sidewalls of a form, a layer of heat-conductive material is carried by the frame in a position to overlie the upper surface of the mix and an electrically energized element is disposed substantially in conductive contact with that layer and produces heat substantially uniformly thereover; another layer of heatinsulating material overlies the heat element. Also disclosed is a flexible blanket that may be placed over the exposed upper surface of a curing concrete mix. The blanket includes one layer of flexible moisture-impervious material substantially reflective to ultraviolet rays and another layer of flexible material substantially reflective to visible light; also preferably included in the blanket is an electrically energized flexible heating element that produces heat uniformly over the surface of the bottom layer.
Heating apparatus comprising: a hollow frame having its major dimensions horizontal and its side walls defining an open top and bottom; a layer of heat-conductive material carried horizontally by said frame to present upper and lower surfaces and disposed between said walls across said top; an electrically energized element disposed substantially in heat-conductive contact with and productive of heat substantially uniformally over said upper surface of said layer; a layer of heat-insulative material overlying said element; means for energizing said element; and means defining an inwardly turned lip around the periphery of said bottom of said frame for supporting said apparatus from and to dispose said layer of heat-conductive material in spaced relationship to a surface to be heated by said element through said open bottom.
Claim 2
Dependent Claim
126 words
Heating apparatus comprising: a hollow frame having its major dimensions horizontal and its side walls defining an open top and bottom; a layer of heat-conductive material carried horizontally by said frame to present upper and lower surfaces and disposed between said walls across said top; an electrically energized element disposed substantially in heat-conductive contact with and productive of heat substantially uniformally over said upper surface of said layer; a layer of heat-insulative material overlying said element; means for energizing said element; and means defining an inwardly turned lip around the periphery of said bottom of said frame for supporting said apparatus from and to dispose said layer of heat-conductive material in spaced relationship to a surface to be heated by said element through said open bottom.
Claim 3
Dependent Claim
30 words
Apparatus as defined in claim 1 in which one of said layers is one of being itself a layer of moisture-impervious material and adjacent to a layer of moisture-impervious material.
Claim 4
Dependent Claim
86 words
Apparatus as defined in claim 1 in which, for curing concrete mix disposed in a slab-shaped form having its major dimensions horizontal and with its side walls having an upper periphery defining an open top through which an upper surface of said mix is exposed, said frame is dimensioned and shaped to mount upon said upper periphery of said side walls and said inwardly turned lip is positioned to dispose said layer of heat-conductive material in spaced relationship to said exposed upper surface of said mix.