Showing papers on "Pervious concrete published in 1991"

Design and Control of Concrete Mixtures

Abstract: This updated, definitive reference book on concrete technology covers the fundamentals and detailed information on freshly mixed and hardened concrete for Canada The properties of concrete as needed in concrete construction are presented, including strength and durability All concrete ingredients are reviewed for their optimal use in designing and proportioning concrete mixtures Applicable standards from the American Society for Testing and Materials, Canadian Standards Association and American Concrete Institute are referred to extensively Individual chapters address: (1) fundamentals of concrete; (2) Portland, blended and other hydraulic cements; (3) fly ash, slag, silica fume and natural pozzolans; (4) mixing water; (5) aggregates for concrete; (6) admixtures for concrete; (7) fibers; (8) air-entrained concrete; (9) designing and proportioning normal concrete mixtures; (10) batching, mixing, transporting and handling concrete; (11) placing and finishing concrete; (12) curing concrete; (13) hot weather concreting; (14) cold-weather concreting; (15) volume changes of concrete; (16) control tests for concrete; (17) high-performance concrete; and (18) special types of concrete

Production of planting concrete block for aquatic plant

Abstract: PURPOSE:To obtain the title concrete block by mixing protective material-coated elements like plant seeds with cement, sand, a foaming agent and water followed by foaming and producing communicating voids in the resultant form. CONSTITUTION:Elements 1 such as the seeds, bulbs or spores of a plant are coated with a water-soluble protective material 2 prepared from e.g. pulp. The resulting elements are mixed with cement, sand, a foaming agent, water, etc., each at an appropriate amount followed by foaming to make a porous concrete 3 to a desired shape. Thus, numerous communicating voids 4 are produced in the concrete 3. Men this concrete 3 is set up on the normal plane of a river, the protective material 2 is lost and the elements 1 will germinate, their roots will also be grown, intrude into the voids, and stretch themselves. And the concrete block is covered with grown aquatic plants 5, and the concrete surface will be covered with these plants, thereby protecting the natural environment.

Studies on Treatment Capability of Open Water Channel using Porous Concrete

Abstract: The pilot plant tests for assessing the application possibility of water channel packing porous concrete to direct purification of polluted river water were conducted. Hence porous concrete provided enough avilable attached area for algae, which was an useful biooxygenproducer, synthetic pollutted river water less than 20mg-TOC/L were sucessfully treated in water channel without deficiency of dissolved oxygen. About 70% of TOC removal was possible under volumetric TOC loading rate below 80 mg/L/day and effluent TOC concentration less than 3 to 4 mg/L could be obtained under volumetric TOE loading rate below 30mg/L/day. Nitrification did not occur in water channel, sothat only 20% of nitrogen was removed. But about 50% of phosphrous was removed by the dissolution of calcium component from porous concrete. Through the SS trapping function of porous concrete, treatment capability of water channel increased tremendously, and the observed sludge yield decreased apparently by the increase of sludge retention time. In water channel packed with porous concrete, filamentous microorganism, such as Geotrichum sp. and Beggiatoasp., andRotariasp., Diplogastersp. andParamecium caudatumwere dominated in the sludge.