US1672380A - Method of curing concrete - Google Patents

Description

Patented lune 5, 1928.

ROBERT B. GAGE, OF TRENTQN, NEW JERSEY.

METHOD or CURING CONCRETE.

Ho Drawing.

The strength of a mass of concrete is dependent upon the even drying, setting and aging of the mass. This is diflicult to rightly accomplished in the manufacture of 1 5 concrete roads and pavements because of the relatively large surface exposed to the dry-. ing action of the air and-sun which tends to dry the surface before the even hydration of the cement has occurred.

To overcome this the surface of a concrete road after it has been placed is sometimes covered with water by building an earth dam on each side of the concrete and across it at intervals. .This is quite costly, and not very practical 'when the pavement is constructed on a grade. Other methods of ouring concrete are straw onburlap, and to keep these materials wetted by sprinkling until the curing of the troublesome not only because of the necessity of frequent sprinkling, but also because it is necessary to prevent the covering from being disturbed by the wind. Burlap or canvas v have also been suspended on frames a short distance above the pavement, but; this is a costly method and the frames are diflicult to keep in place in windy weather.

I have discovered that a more efficient and more economical method of accomplishing the even drying and setting of concrete is to cover the surface of the concrete after it has been'placed, with a layer of bituminous felt or other heavy paper saturated or coated with a waterproof bituminous layer. Ordinary roofing felt answers the purpose well.

This material, difier'ing from those previously used for the purpose, is waterproof, so that the sun and air acting upon the upper surface of the covering do not draw up an evaporate the moisture of the upper surface.

of the concrete; but, on the contrary, the moisture is retained beneath the bituminous felt so that the upper surface of the concrete is kept moist and consequently cured at a Application filed August 15, 1925. Serial No. 50,483.

to cover the surface with concrete has been accomplished, but this isd maintaining such covering until the concrete surface is completely and evenly set.

rate more nearly corresponding to that of the lower part of the concrete which is in contact with the damp ground. Furthermore bituminous felt is highly absorbent of heat and the warmth of the subjacent concrete thus created helps the even hardening of the concrete, and also prevents freezing on frosty nights. At the end of a few days the curing is accomplished and the covering is removed.

I am aware that various absorbent coverings have been employed to protect the surface of freshly laid.concrete from the cold and to prevent it from freezing. I am also aware of the use of various dampened surfaces as I have above described to prevent the too rapid drying of the upper surface of the concrete by the atmosphere and the sun.

My invention differs from these in thatI employ as a temporary covering a felt paper which has been rendered waterproof or nonabsorbent of water, by the application of a bituminous saturation orcoating. I believe this to be novel, and I have found that it is highly efficient for the reasons which I have 7 previously explained.

Having thus described my invention, I claim:

1. The method of curing concrete which consists in placing the concrete and then temporarily covering the surface thereof which is exposed to the atmosphere with a non-absorbent bituminous felt, untilthe even curing of the concrete is accomplished.

2. The method ofmaking a concrete pavement which consists in placing a layer of concrete upon a' suitable foundation; and temporarily covering the uppersurface thereof with a'layerof bituminous felt, and

In testimony whereof, I have hereunto signed my name at Trenton, New Jersey, this 6th day of August, 1925. u

' ROBERT'B. GAGE.