Showing papers on "Pervious concrete published in 1997"

Observations of Infiltration Through Clogged Porous Concrete Block Pavers

Abstract: James and Verspagen (1996), Thompson and James (1995), and Shahin 1994) have observed low runoff volumes from porous concrete paver laboratory test blocks used…

Concrete block for water purification

Abstract: PROBLEM TO BE SOLVED: To efficiently remove sludge in water by the filtering effect of a water-permeable concrete block and the filtering and adsorbing effect of a powdery carboraceous material by sealing the powdery carbonaceous material in the water-permeable concrete block SOLUTION: This concrete block 1 for purification of water to be used as a material to purify and filter water in a river consists of a water-permeable concrete block hollow body 2 comprising a water-permeable concrete block and a powdery charcoal (powdery carbonaceous material) 3 sealed in the water- permeable concrete block hollow body 2 The powdery charcoal 3 is housed in a water-permeable bag 3A such as a nonwoven fabric or a woven or knitted fiber material By putting a plurality of the concrete blocks 1 thus obtd in a weir formed just under a step in a river, the water in the river can be purified

Paving method of water-permeable concrete

Abstract: PROBLEM TO BE SOLVED: To carry out pavement on a field such as a roadway, a sidewalk, a cycling way, a parking space, a place, etc. SOLUTION: A water-permeable concrete base layer is paved on a sand filter layer and a crushed-stone base layer paved on the ground so that the percentage of voids after the completion of curing is maintained within 10-20% and the coefficient of permeability reaches 10×10 cm/sec or more. Crushed waste glass, fine crushed stones, cement having strength of 250kg/m -500kg/m , water at the ratio of 25-40% of water/cement(W/C), and a polymer of 10-50% of the weight of cement used based on a solid content of 50% as a reference are mixed, and the mixture is paved on the base layer and solidified. The mixture is cured for one day or more, and the polymer and water are mixed and scattered so as to be permeated to the above-mentioned water-permeable concrete base layer and cured, thus completing pavement.

Instantaneously demoldable porous concrete molding and its production

Abstract: PROBLEM TO BE SOLVED: To obtain an instantaneously demoldable porous concrete molding having high bending strength and large permeability coefficient and suitable for a water permeable interlocking concrete block or the like usable even for drive way. SOLUTION: This instantaneously demoldable porous concrete molding is obtained by combining particle bodies, each of which is formed by covering a coarse aggregate with a paste or mortal having 150-300mm consistency as paste flow or mortal flow of 1-mm average thickness, through the paste or mortal part, and has 5.0-7.0N/mm bending strength and 0.3-3.0cm/sec permeability coefficient.

Surface treatment of precast concrete perforated pipe

Abstract: PROBLEM TO BE SOLVED: To prevent fissure, crack and deterioration and to prevent the damage of an inserted cable by applying a permeable concrete strengthening agent of a water glass system on the concrete surface of a precast concrete perforated pipe. SOLUTION: If the outside surface of the perforated pipe is in a gritty state, the chemical materials included in rainwater and ground water are liable to penetrate such pipe and the deterioration of the pipe is worried. If the inside surface of the pipe is in the gritty state, the danger of damaging the cable at the time of insertion is high. An aq. soln. of sodium silicate expressed by Na2 O.nSiO2 (n is 2 to 4) is used as the chief material of the strengthening agent. This agent permeates the concrete and reacts with the calcium compd., aluminum compd., etc., in the concrete to form glass-like cured matter, thereby filling the gaps among the pores on the surface, making the surface structure denser and smoother and increasing its strength. While a method of applying the agent by immersing the pipe for specified time in a strengthening agent bath is simple and sure, the application of the agent on the inside and out of the pipe by the procedure for spray coating is equally well.

Greening block and its manufacture and the greening block execution method

Abstract: PROBLEM TO BE SOLVED: To improve the strength of the joint of frame concrete and vegetation concrete and efficiently manufacture a slope face block in a short period of time. SOLUTION: There are provided a step in which concrete (a) is placed in a frame concrete section 21 of a form 20 to form a frame concrete 1, a step in which porous concrete (b) is placed in a vegetation concrete section 22 of the form 20 before the frame concrete 1 is solidified to form a vegetation concrete part 10, and a step in which the frame concrete 1 and vegetation concrete 10 of integral construction are simultaneously cured and removed from the form.

Method of constructing water permeable pavement, and water permeable tile

Abstract: PROBLEM TO BE SOLVED: To provide a method of constructing a water permeable pavement with high adhesion and high water permeability and a water permeable tile suitable therefor. SOLUTION: A sub base 2 consisting of crushed stone is formed on a subgrade 1. A water permeable concrete layer 3 is formed on the sub base 2. A water permeable tile 5 is adhered onto the water permeable concrete layer 3 in dot or mesh form. According to this, high adhesion and water permeability can be ensured. A water collecting pipe 6 is arranged in the water permeable concrete layer 3 to purify and collect rainwater. The collected water is guided to a storage pit 11 through a storage tank. The storage pit 11 is provided with a storage pump 13 to circulate and reuse the water. As the water permeable tile 5, shirasu is used in addition to conventional silica rock, crushed stone, or crushed matter of tile, pottery, or glass. Thus, a lightweight and highly water permeable one can be provided at a low cost. COPYRIGHT: (C)1999,JPO

Planting concrete block

Abstract: PROBLEM TO BE SOLVED: To provide a high quality planting concrete block by employing hard material with a water absorption rate reconditioned in a specified range as skeleton material to form a porous concrete. SOLUTION: As cement to form a porous concrete block, portland cement is used. Skeleton material to be mixed with the cement has a water absorption rate of 6-20%, preferably 10-15%. The skeleton material is one or two types of stones, roof tiles, blicks, tiles or the like mixed. The porosity of the porous concrete block is 25-40% but preferably 25-35% from the points of strength and vegetation, on account of which the maximum size and the uniformity coefficient of the skeleton material are 25-10mm and 1.5 or less, respectively. The porous concrete block contains cement, skeleton material and water mixed together, filled in a form and then compacted with a vibrator in manufacturing.

Cathodic Protection of Reinforcing Steel in Concrete Structures

Abstract: Publisher Summary The chapter discusses the deficiencies in the thickness and the density of concrete structures that require additional corrosion protection measures in a construction process. The corrosion protection of reinforcing steel in steel-reinforced concrete and prestressed concrete structures acts through the alkalinity of the porous concrete water content because the steel passivates under many conditions. The application of cathodic protection to reinforced concrete structures requires proper technical and economic considerations such as design and installation; determination of the state of corrosion of the reinforcing steel; assuming an extended electrical continuity through the reinforcing steel; making use of different concrete replacement systems for cathodic protection and proper maintenance; and commissioning and control of the cathodic protection. Cathodic protection cannot work with prestressed concrete structures that have electrically insulated, coated pipes. There is a positive experience in the case of a direct connection without coated pipes; this is the protection of buried prestressed concrete pipelines by zinc anodes.

On-site execution method of water permeable type concrete

Abstract: PROBLEM TO BE SOLVED: To eliminate generation of problem in association with drying of water permeable type concrete by applying aqueous polymer dispersion on the surface of the concrete spreaded, and applying thereto fastening and finishing work. SOLUTION: After the application of aqueous polymer dispersion on the surface of water permeable concrete spreaded, fastening and finishing work is carried out. Accordingly, even if drying of the concrete generates before the work, the dispersion permeates the inside of the concrete along a gap therein by the aid of vibration fastening operation applied thereto, and aggregate members are connected integrally with cement paste while fluidity of dried paste is resumed for improving charge performance. When the dry condition is remarkable. water required for solidifying cement is supplied. With these actions, partial decrease in strength resulting in separation of aggregate material on the surface of water permeable type concrete is prevented.

Method for forming porous concrete

Abstract: PROBLEM TO BE SOLVED: To provide an easy and inexpensive method for forming a porous concrete enabling the rooting of even a large-sized plant at a low production cost. SOLUTION: A number of string-shaped pore-forming members 1 made of a biodegradable plastics are mixed into a water-permeable concrete 5 and the mixture is placed to form the objective porous concrete C. The amount of the pore-forming members 1 may be increased at the surface layer of the porous concrete C at a depth of 30-40cm in the placing of the water-permeable concrete 5. It is also possible to form spaces in the pore-forming members, fill the space with soil mixed with seeds and open holes on the surface to connect the inside to the outer atmosphere.