| 摘要 |
Porous concrete Material with good permeability to water is made from a mix contg. cement a granular mineral aggregate with a uniform particle fraction in the range 3-30 mm and a tolerance range of 4-15 mm, 0.05-2 wt. % (based on cement) of a macromolecular water soluble material, and water such that the water/cement ratio is 0.32-0.48. Prefd. filler is washed and graded gravel with round or oval particles. Up to 5% asbestos fibres are be present, as well as non-ionic surface active agents. The macromolecular cpds. are water-sol cellulose ethers, alkali salts of polyacrylic acid, polyacrylamides. The products can be sprayed as layer up to 25 cm thick and harden to porous concretes with high strength, useful in tunnel and mineshaft construction. |
