Abstract: A method of manufacturing a waffle slab includes providing a bottom mold separately on columns and exposing joint heads of the columns from the bottom mold; providing first sets of beam bars separately on the bottom mold to be parallel along a first direction; and providing second sets of beam bars separately on the bottom mold to be parallel along a second direction, wherein the second sets b of beam bars are configured to intersect with the first sets of beam bars without interference and together they form accommodation spaces for waffle molds.

Abstract: A liquid dispersed dye of the azo or anthraquinone type that includes a dispersing agent and dispersing assistant in order to keep the dye dissolved in liquid without sedimentation. The preferred dispersing agent is a sulfonated lignin salt and the preferred dispersing assistant is a surfactant such as polyethylene glycol epoxide ether (EO-1), polyethylene glycol phenolic-formaldehyde epoxide ether (EO-2), or polyethylene glycol amino methylene epoxide ether (EO-3).