| OCR Text |
Show Different Ways to Cure Newly Placed Concrete . Recent survey of numerous highway high-way construction projects show that contractors employ different methods te cure newly-laid concrete. This curing cur-ing Is said to be one of the very Important Im-portant processes In building a first-class first-class concrete pavement. . On level sections of highway, the preferred method, It was found. Is the building of earth dykes along the edges pf the pavement and flooding the Inside In-side area as shown In the illustration. The water Is then kept on the surface of the concrete for ten days or two weeks. This method was thought to be cheaper than covering with earth because of the labor necessary to shovel the dirt on to the pavement and later clean It off. The water required re-quired to keep the earth wet was about as much as If the surface of the pavement was flooded. j Sone contractors reported that the use of hay was best. They said It would hold more water and could be r : 4-1 i Curing Newly-Laid Concrete by Flooding. Flood-ing. used several times over. Moreover, It was not hard work to distribute tha hay or rake it up after the curing period. Where water was plentiful, some contractors expressed themselves in favor of using sprinklers. A water pipe was laid down the center of the road, with lawn sprinklers attached at frequent intervals. These were kept niiinlnc aevprnl honra a day. The advantages of one or another method of curing were not found to be such as to affect the strength or wearing qualities of the concrete. Although Al-though concrete begins to harden soon after It is mixed, the full strength Is developed by progressive hardening over a period of time. The hardening process Is said te be not a drying process, as the presence of moisture is necessary to assist the chemical action which causes concrete to harden. |
