Curing Period Haunch boards (side forms on girders and beams) and wall forms can usually be removed after 1 day. Column forms usually require 3 days before the forms can  be  removed.  Removal  of  forms  for  soffits  on girders and beams can usually be done after 7 days. Floor  slab  forms  (over  20-foot  clear  span  between supports) usually require 10 days before removing the forms. Inspections After removing the forms, the concrete should be inspected for surface defects. These defects may be rock  pockets,  inferior  quality  ridges  at  form  joints, bulges,   bolt   holes,   and   form-stripping   damage. Experience has proved that no steps can be omitted or carelessly   performed   without   harming   the serviceability of the work. If not properly performed, the repaired area may later become loose, crack at the edges, and not be watertight. Repairs are not always necessary, but when they are, they should be done immediately  after  stripping  the  forms  (within  24 hours). Defects  can  be  repaired  in  various  ways. Therefore,  let’s  look  at  some  common  defects  you may  encounter  when  inspecting  new  concrete  and how repairs can be made. RIDGES AND BULGES.—  Ridges and bulges can  be  repaired  by  careful  chipping  followed  by rubbing with a grinding stone. HONEYCOMB.—  Defective   areas,   such   as honeycomb,  must  be  chipped  out  of  the  solid concrete. The  edges  must  be  cut  as  straight  as possible  at  right  angles  to  the  surface  or  slightly undercut to provide a key at the edge of the patch. If a  shallow  layer  of  mortar  is  placed  on  top  of  the honeycomb concrete, moisture will form in the voids and subsequent weathering will cause the mortar to span off. Shallow patches can be filled with mortar placed in layers not more than 1/2-inch thick. Each layer  is  given  a  scratch  finish  to  match  the surrounding concrete by floating, rubbing, or tooling or on formed surfaces by pressing the form material against the patch while the mortar is still in place. Large or deep patches can be filled with concrete held  in  place  by  forms. These  patches  should  be reinforced  and  doweled  to  the  hardened  concrete (figure  7-54).  Patches  usually  appear  darker  than  the surrounding concrete. Some white cement should be used in the mortar or concrete used for patching if appearance is important. A trial mix should be tried to determine the proportion of white and gray cements to use. Before mortar or concrete is placed in patches, the  surrounding  concrete  should  be  kept  wet  for several hours. A grout of cement and water mixed to the consistency of paint should then be brushed into the  surfaces  to  which  the  new  material  is  to  be bonded. Curing should be started as soon as possible to avoid early drying. Damp burlap, tarpaulins, and membrane-curing   compounds   are   useful   for   this purpose. BOLT HOLES.— Bolt holes should be filled with small amounts of grout carefully packed into place. The grout should be mixed as dry as possible, with just enough water so it compacts tightly when forced into   place.   Tie-rod   holes   extending   through   the concrete can be filled with grout with a pressure gun similar to an automatic grease gun. ROCK  POCKETS.—  Rock  pockets  should  be completely chipped out. The chipped out hole should have sharp edges and be so shaped that the grout patch will  be  keyed  in  place  (figure  7-55).  The  surface  of all holes that are to be patched should be kept moist for  several  hours  before  applying  the  grout.  Grout should be placed in these holes in layers not over 1/4 inch thick and be well compacted. The grout should be allowed to set as long as possible before being used to  reduce  the  amount  of  shrinkage  and  to  make  a better  patch.  Each  layer  should  be  scratched  rough  to improve the bond with the succeeding layer and the last layer smoothed to match the adjacent surface. Figure 7-54.-Repair of large volumes of concrete. 7-32