Ultra lightweight foamed cement based composite material and method

The invention relates to an ultra-light cement-based composite foaming material and a preparation method thereof. The preparation method comprises: uniformly stirring cement, fly ash, water reducer, foam pore regulator, pulp thickness regulator, fiber, foam stabilizing agent and mixing water to prepare pure pulp; diluting a physical foaming agent by 20 folds and making foam by a mechanical means;mixing the made foam into the stirred pure pulp, stirring uniformly again and obtaining foam pulp; adding a chemical foaming agent and a foaming accelerator into the obtained foam pulp, and pouring into a mold preheated to 40 DEG C; after the pouring is finished, curing the mold in a constant-temperature curing chamber at 40 DEG C, curing for 24 to 32 hours, demolding, and obtaining the ultra-light cement-based composite foaming material. In the invention, the foaming material is prepared by a method of combining physical foaming and chemical foaming; and the obtained product is low in density and very light, reaches a fireproof grade A, has a long service life and excellent comprehensive performance and is suitable to be widely used.