Showing papers on "Pervious concrete published in 1995"

Building and Nonpavement Applications of No-Fines Concrete

Abstract: No-fines concrete is defined as a type of concrete from which the fine aggregate component of the matrix is entirely omitted. The aggregate is of a single size and the finished product is a cellular concrete of comparatively low strength and specific weight. The cellular nature eliminates capillary attraction and provides greater thermal insulation and water permeability than exists in conventional concrete. The advantages of no-fines concrete for different construction purposes have long been recognized. The post–World War II era has experienced the extensive use of no-fines concrete for load-bearing walls in single and multistory buildings, retaining walls, and ground-drainage slab systems. This paper traces the development and applications of no-fines concrete for building and other nonpavement purposes. The pavement applications are introduced in a companion article published in the ASCE Journal of Transportation Engineering .

Optimizing surface texture of concrete pavement

Abstract: In earlier days, roads were designed and constructed only as load carriers--no attention was given to road surface characteristics. The goals of concrete finishing were directed only to achieving a surface free from defects. However, as traffic volume and vehicle speeds increased, pavement skid resistance and traffic noise became major concerns. Highway engineers were forced to look for ways to improve skid resistance of concrete pavements, and to reduce tire/road noise. While proved to be the best technique to enhance the skid resistance of concrete pavements, surface texturing also has a major influence on tire/road noise. This report summarizes current and past research and development work related to surface texturing technology. It begins with experiments on skid resistance in the early 1930s in Iowa and Ohio and continues through the recent developments in exposed aggregate and porous concrete in Europe. Reports and publications are summarized on the work done in this field in the last 60 years with emphasis on concrete pavement friction and tire/road noise issues. Various surface texturing techniques discussed in this report include burlap dragging, transverse tining, longitudinal tining, exposed aggregate, chip sprinkling, surface dressing, and porous.

Sound absorption concrete, sound absorption concrete unit, sound absorption concrete block, sound absorption concrete wall using them and production of the concrete and block

Abstract: PURPOSE: To obtain the sound absorption concrete, sound absorption concrete block and sound absorption concrete wall using them which are inexpensive and excellent in noise absorptivity and durability, without needing a severe producing condition as in a porous concrete sound absorbing material and capa ble of being produced with a process equivalent to that for an ordinary concrete product. CONSTITUTION: A sound absorption concrete 11 consisting of an aggregate having =0.8kg/l unit volume mass and a hydrated material obtained by hydrating and solidifying 250-400kg per m aggregate of a material to be hydrated and solidified is obtained. This sound absorption concrete has 20-55% appearant porosity and >=80% maximum noise absorption. The concrete 11 is stuck to a slope surface block 12 or integrated with the block 12 to obtain a sound absorption concrete block 10, and the plural blocks are arranged to obtain a sound absorption concrete wall 20.

Measuring is knowing

Abstract: As a result of the need for standard measuring methods to assess the acoustic properties of road surfaces in an objective way, this article discusses different measuring methods for this purpose. For measuring the traffic noise level as experienced by homes and businesses near the roadside the Statistical Pass-By method (SPB method) can be used. For measuring the design parameters texture and absorption of the road surface, measurements with a profilometer and measurements by means of drilled cores in an impedance tube are carried out respectively. To check whether the road has been constructed in accordance with the acoustic specifications, the so-called trailer method can be used. A trailer with a standard test tyre and a microphone close to the tyre/road contact area is used here. Next, the results of noise measurements according to the SPB method on three types of concrete roads are discussed: 1) brushed concrete; 2) concrete with exposed surface aggregate; and 3) porous concrete. These results indicate the noise production of these types of concrete roads. Dense asphaltic concrete 0/16 is used as a reference road surface.

Concrete blocks` adverse effects on indoor air and recommended solutions

Abstract: Air infiltration through highly permeable concrete blocks can allow entry of various serious indoor air pollutants including radon. An easy approach to avoiding these pollutants is to select a less-air-permeable concrete block. Tests show that air permeability of concrete blocks can vary by a factor greater than 50 (0.63--35 standard L/min/m{sup 2} at 3 Pa). The surface texture of the blocks correlates well with air permeability; test results of smoother, closed-surface-texture blocks were usually less air-permeable. During construction, air infiltration can be minimized by capping walls and carefully sealing around openings for utilities or other penetrations. Structures with indoor air-quality problems due to soil-gas entry can be mitigated more effectively with less coating material if the blocks have a closed surface texture. All coatings evaluated--cementaceous block filler (which has the lowest applied cost and is more than 99.5% effective), surface bonding cement, water-based epoxy, polysulfide vinyl acrylic, and latex (three coats)--were highly effective (more than 98%) in reducing air permeability when adequately applied. Coating selection should be influenced by expected service life, considering surface condition and cost.

Process for the manufacture of a water-permeable concrete structure, and structure produced with this process

Abstract: Process for the manufacture of water-permeable concrete structure, including the steps consisting in: - preparing a concrete composition consisting of: - 300 to 400 kg of cement per m of the concrete composition, - 0008 to 004 part by weight of binder per part by weight of cement, - 03 to 045 part by weight of water per part by weight of cement, and - 1,790 to 2,150 kg of granulate per m of the concrete composition, the granulate including, on the one hand, sand and, on the other hand, crushed stone and/or gravel, in a weight ratio of between 5:95 and 20:80, the said crushed stone having a particle size of 25 to 5 mm and the said gravel a particle size of 5 to 10 mm, - allowing the concrete composition to set to form a water-permeable concrete structure, and - applying water under very high pressure to the surface of the concrete structure, with a pressure of 1,000 x 10 Pa to 2,500 x 10 Pa, in order to scour the granulate which covers the set cement mortar in a surface layer of the concrete structure

Porous concrete for vegetation

Abstract: PURPOSE:To obtain a porous concrete for vegetation, having a mixture such as cement and a housing unit filled with the mixture, capable of providing soil suitable for growth of a plant in interstitial parts among aggregates and excellent in strength. CONSTITUTION:This porous concrete 1 for vegetation has (A) a mixture prepared by mixing cement with aggregates 11 and a granular or a massive organic substance such as cereals 12 smaller than interstices among the aggregates 11 and water and (B) a housing unit 2 filled with the component (A).

Process and device for producing bodies of gas concrete (porous concrete, aerated concrete) or the like

Abstract: In a method for producing bodies of gas concrete or the like, in which firstly a pourable, curable slurry comprising the basic materials for the body is produced, then an expanding agent (foaming agent) is added and the mass obtained is poured into a moulding box (2), provision is made, in order to reduce the size and number of the air inclusions remaining in the finished gas-concrete body, substantially before the beginning of the rising process, for a screen arrangement (8) having a mesh size which entrains damaging inclusions to be drawn through the mass and out of the latter.

Porous concrete pipe for pouring into mould

Abstract: The pipe comprises a water inlet at one end (10) of the pipe (3), while the latter is connected at the other end (11) via a controllable valve (12), and a pipe (14), to the collecting tank (15). The same inlet can be used both for the liquid concrete and the water. The internal cross-section of the pipe is cylindrical and flattened at the bottom. Its diameter in relation to the pouring outlet cross-section is such that with the outlet open the concrete can spread over the whole pipe length before flowing out.

Asphalt concrete road covering

Abstract: The temporary layer of soluble starch is used on roads with very open (porous) asphalt/concrete, or very open (porous) concrete, to combat slippery conditions. The temporary layer takes up moisture from the environment, then swells and take on a solid form. After a while the mass becomes liquid again, to flow away from the asphalt/concrete or very porous concrete.

Investigation into porous concrete formation peculiarities with a mixed binder composition

Abstract: Summary Porous concrete is a cheap material produced from local raw materials That is why, it is important to improve it's properties, especially the product's density This paper deals with porous concrete made using a mixed binder composition (lime+Portlandcement) formation peculiarities and determination of optimal product formation parameters for 300–350 kg/m3 product dependency on the binder mixture composition A wide density interval (200–500 kg/m3) was investigated to determine the optimal above mentioned porous concrete density parameters It was determined, that the porous concrete density with a mixed binder composition has a complex dependency from water and dry solids ratio (V/K), mixed binder composition and amount of Al powder Mathematical equations of porous concrete density on technological parameter were derrived It was found that the lime contant increase in the lime- Portlandcement binder mixture, lowers Al powder effectiveness, increases the product's density and decreases the tech

Production of concrete board with sound absorbing board

Abstract: PURPOSE:To easily produce a concrete board integrally bonded with sound absorbing boards. CONSTITUTION:The sound absorbing boards 4, 4 consisting of lightweight and porous concrete are laid within a form 1 for molding a concrete board and the respective joints are filled by a joint material 5. Water is then sprayed on the sound absorbing boards 4, 4 and absorbed therein and thereafter, arrangement of bars are arranged therein and ready mixed concrete 8 is placed in the form. The concrete is then molded by curing. The sound absorbing boards 4, 4 do not absorb the water of the ready mixed concrete 8 and, therefore, the sound absorbing boards 4, 4 and the concrete 8 are securely bonded and integrated.

A methot for making a various density porous concrete

Abstract: The invention applies to the production of stratified construction articles. The method consists of the form filling by a cellular concrete mix of various density. Before filling a cellular concrete mix at least one vertical partition is put into the form and then partition made compartments are filled with the mix of various density cellular concrete. Afterwards the partition is taken out in synchronisation to the bulging speed of the cellular concrete. Using this method there it is able to produce a cellular concrete of a different body volume.

Matrix-shaped block

Abstract: PURPOSE:To enable a large number of concrete lumps provided with gaps length wise and crosswise and connected to each other to correspond freely with a form of the objective surface of execution such as an uneven slope, etc, and to build them by connecting the concrete lumps mentioned above in a displaceable manner CONSTITUTION:Concrete lumps 2 such as a large number of imitation rocks or stone are arranged lengthwise and crosswise with gaps As the concrete lumps 2, for example, porous concrete, resin concrete, etc, are used After that, the concrete lumps 2 are connected to each other with connection members 3 to from a matrix-shaped block 1 At that time, as the connection members 3, for a example, a pair of shaped reinforcements are used, and their ends are buried in the concrete lumps 2 For example, while displacing the concrete lumps 2 in correspondence with the unevenness of a slope of a revetment, the matrix-shaped block 1 is built Even if there is a scour in the slope, the concrete lumps 2 can be prevented from being separated from the slope by the operation of the connection members 3

Composite concrete revetment

Abstract: PURPOSE:To protect the face of a slope of a shore by normal concrete of a lower layer, and vegetate plants on the face of the slope by a porous cocrete layer of an upper layer so as to give rise to natural environment. CONSTITUTION:A normal concrete layer 2 is provided on the surface of slope 1, and a porous concrete layer 3 is formed on the layer 2. Otherwise, a hollow part 4 is provided between the normal concrete layer 2 and the porous concrete layer 3, and soil, water retentive material, rearing material, and the like are filled therein. Otherwise, a storage part for storing soil, water retentive material, rearing material, and the like is provided between both layers.