Showing papers on "Screed published in 1990"

Performing Organization Name and Address

Abstract: The results of a study undertaken to evaluate premixed polymer concrete overlays (PMPCO) over a 3-year period are presented. The PMPCO evaluated were constructed with polyester amide para resin and silica sand 1;. polyester styrene resin 1 and silica sand 2; polyester styrene resin 2, basalt aggregate and coke breeze (for conductivity); polyester styrene resin 2, silica sand 3 and coke breeze; and vinyl ester styrene resin, silica sand 2, and coke breeze. The mixing of the ingredients was done with either portable concrete mixers, mortar mixers, or a continuous batching mobile concrete mixer. The overlays were struck off and consolidated with a vibrating screed or a slip form paver. The report indicates that a nonconductive PMPCO with high bond strength, low permeability, and high skid resistance can be successfully installed by a contractor and opened to traffic after only three hours of curing. The report indicates that a conductive PMPCO with high bond strength and skid resistance can be successfully installed as a secondary anode for a cathodic protection system. Also, it is shown that the special provision for a PMPCO should require the installation of test patches or test sections of overlay prior to placing the final overlay to assure that the surface preparation is adequate and the mixing, installation equipment, procedures, and materials will provide a satisfactory overlay.

Method and apparatus for heating a paving screed via liquid circuit heat transfer

Abstract: A paving machine screed is heated by pumping fluid from a reservoir tank mounted on the screed to a flow restrictor so that the fluid is heated by a pressure drop across the at the flow restrictor and returned to the tank for heat transfer to the screed.

Concrete path paver with removeable slip-forming screed

Abstract: Apparatus for slip-forming concrete to form a path comprising in combination a box having a front wall extending downwardly through the box, and a rear wall extending downwardly at an angle through the box to a location above the front wall, and opposing side walls coupling the front and rear walls extending downwardly to define the closed box having an upper opened end for receiving concrete and a lower opened end with a vertically disposed opened mouth defined by the vertical edges of the side walls and the lower edge of the rear wall, with the lower opened end having a smaller cross-sectional area than the upper opened end, and a screed for slip-forming the concrete, means for removably securing the screed at its edges to the side walls below the rear wall with the forward end of the screed being positioned at the opened mouth of the rear wall.

Windrow paving machine and method of paving

Abstract: A windrow-type paving machine movable along a windrow of paving material includes a loading conveyor operable to transfer the upper portion of the paving material within the windrow into a hopper. The remainder of the paving material remains on the roadway and passes through a tunnel formed in the paving machine to a lateral auger and screed which cooperate to spread and level the paving material. The machine provides a hopper which receives the upper portion of the paving material for subsequent delivery by a conveyor to the lateral auger and screed when insufficient paving material passes through the tunnel to produce the required paving. Agitator means are provided in the tunnel to break up lumps of paving material and the like before they reach the auger.

Screed slope controller for a paver

Abstract: A controller for controlling the slope of a screed supported by support arms wherein the screed is moved over a distance includes a first slope sensor which develops a first sensor signal representing the slope of the screed, a second slope sensor which develops a second sensor signal representing the slope of the support arms and a first summer which sums the first sensor signal and command signal indicative of a particular screed slope to develop a first error signal. An integrator integrates the error signal over distance to develop an integrated first error signal. A second summer sums the integrated first error signal with the second sensor signal to develop a second error signal which is utilized to control actuators which adjust the slope of the support arms.

Pavement thickness controlling method for paving machine

Abstract: PURPOSE: To flatly finish the surface of pavement by a method wherein the difference in height between unpaved surface on a target point positioned forward in the direction in which a screed travels and a straight datum flatness line is obtained, and the screed is controlled in accordance with the difference. CONSTITUTION: Paving material is laid and rolled with a screed 5 as a vehicle 1 travels. Each time the vehicle 1 travels the distance between a first height sensor 13 and a second height sensor 14, the sensors 13 and 14 and a gradient sensor 15 measure respectively the distances to the road surface and the tilt of a measuring arm 12, and a distance sensor 17 measures the distance of travel. All the measured results are outputted to a computing unit. The computing unit obtains, by computing, the difference in altitude and the pavement thickness, and obtains a straight datum flatness line by computing. Then the difference between a control target value and an actual value of the 1 measurement by a third height sensor 19 is obtained, and the screed 5 is controlled with a pivot cylinder 8 that is made operable in expansion and contraction so that the difference becomes zero. Each time the vehicle 1 travels specified distance, judgement is made whether the thickness of actual measurement agrees with the target pavement thickness, and correction is made when the actual thickness is beyond the specified extent. COPYRIGHT: (C)1992,JPO&Japio

Concrete pumping and spraying

Abstract: * Concrete pumping plant and equipment * Capabilities of concrete pumps and special applications * Cost comparisons - pumping and other methods of placement * Pumpable concrete * Concrete pumping operations on site * Common problems and corrective measures * Hints for the man on site * Safety and training * Screed pumping * Sprayed concrete * Concrete pumping - the future.

Sport-hall flooring

Abstract: In the case of a sports-hall flooring, in particular for gymnasiums, having a flexible layer applied on an underflooring or naked flooring of screed or the like, on which layer an impact-absorbing and force-absorbing layer is arranged, if appropriate with a film of plastic or the like in between, the impact-absorbing and force-absorbing layer comprises at least two plies of polyolefin sheets. The polyolefin sheets of at least one ply have on their surface facing the other ply a nonwoven fabric and are bonded to the other ply with the nonwoven fabric being incorporated.

Heated building panel

Abstract: A building panel designed to reduce condensation on the internal surfaces of buildings comprises, in sequence, a steel decking 10, an underlayer screed 11 of settable lightweight epoxy resin in which are embedded electrical surface heating cables 12, a layer of bitumen emulsion adhesive 15, a thermally insulating layer 16 of cellular glass insulation, a further layer 18 of bitumen emulsion adhesive, a load-spreading layer 19 of expanded metal and a surface deck screed 20. The heating cables 12 maintain the steel decking 10 a sufficient temperature to inhibit condensation. The panel can be used as a roof surface which can also be used for work and the storage of equipment. Versions of the panel without some of the strengthening layers may be used for walls and roofs where less structural strength is necessary.

Sports-hall floor

Abstract: The invention relates to a sports-hall floor, in particular for gymnasiums, having an elastic layer which is applied on a subfloor or unfinished floor consisting of screed or the like and on which at least one impact-absorbing and force-absorbing layer is arranged, if appropriate with the interposition of a plastic sheet. The impact-absorbing and force-absorbing layer comprises a sandwich element of high rigidity.

Prefabricated floor slab

Abstract: The invention relates to a prefabricated, concrete flooring slab (1) provided with reinforcement steel (10), and after erection intended to be provided with a screed (4) or like concrete pouring. So that the finished structure shall function as a unit, from the loading aspect, shear forces from the poured concrete (4) must be effectively taken up by the slab (1). For this reason, the slab is provided with recesses (2) at opposing end portions on its upper side, such that when the slab is loaded they can take up shear forces coming from the poured concrete, these recesses being provided with arched reinforcing bars (5, 6) forming lifting eyes and extending up from the bottom of the recesses (2) to a height such that the intended poured concrete (4) will cover the lifting eyes.

Road leveller for pavement

Abstract: PURPOSE:To pave and level highly dense steel fiber concrete by providing a screed having a vibrating slope plane and two sets of dampers alternately moving up and down on the rear part of a hopper provided with a screw spreader, in order. CONSTITUTION:A paving and levelling device 5 provided with wheels 7 is connected to a concrete finisher. Nextly, steel fiber concrete in a hopper 11 is spread in the hopper 11 with a screw spreader 13, while running the device 5 on a rail 9. Nextly, vertical vibration is given to level the concrete with a screed 23 provided with a slope plane 23b and a vibrator 28. Widthwise long plate-like dampers 30, 31 are alternately moved up and down to forcedly press the concrete, while loosing entangled or projected steel fiber. Hereby, steel fiber concrete can be efficiently and high-densely paved and levelled.

Floor structure for insulating footfall sound and method of preparing the same

Abstract: The invention relates to a footfall-sound insulating floor structure which comprises a layer approx. 15-35 mm thick of a cement-based, fiber-reinforced, self-leveling, rapidly hardening, rapidly drying and shrinkage-compensated slurry screed cast on top of a footfall-sound insulating material layer, this layer combination being formed either on top of a new concrete floor having a thickness determined by the footfall-sound standards, alternately the strength standards, or as a renovation layer on top of an already existing load-bearing base. The invention also relates to a method for forming such a floor structure.

Material receiver and its method

Abstract: PURPOSE: To quickly discharge load to a hopper by providing a chassis capable of receiving material, a means for leading the material with a conveyor for discharge, and a trough for receiving the material from a delivery vehicle, and moving the material inside of a dump hopper to an inlet so as to reduce the pile. CONSTITUTION: A self-promoting storage vehicle 10, a caterpillar type floating finishing machinery 12 and a delivery dump truck 16 with a deck 17 are provided. The finishing machinery 12 is provided with a conveyor 19a for feeding the asphalt-aggregate material from a hopper 14 to a position right in front of a screed and a lateral screw auger 19b. The discharging conveyor 19a is rocked in the vertical direction so as to discharge the asphalt-aggregate material to an upper expanded hopper 14. The asphalt-aggregate material is quickly and easily discharged to a trough 38 having the same width with the deck 17 of the supplying truck. With this structure, transference of the material from the truck to the conveyor is facilitated.

Method for manufacturing floor coverings.

Abstract: A method of manufacturing floor coverings from inorganic materials, such as in particular a floating screed, is used to join together prefabricated panels (1), having a peripheral groove (3), by means of springs (5) to form a closed surface. In comparison with a floating screed laid by conventional methods, the use of prefabricated panels (1) dispenses in particular with the setting time of the screed, dependent upon manufacture and material, which previously delayed the progress of construction considerably. In addition, the panels can be examined for their quality before laying.

Nottinghamshire's road ramps scheme

Abstract: The ramps are constructed of thermoplastic screed built up in layers to form a castellated profile. Their design is shown in Fig. 1. They have been shown to be effective in reducing the speed of vehicles approaching the junction and have not proved detrimental to road-users

Paving machine and road paving method

Abstract: PURPOSE: To improve the efficiency of the paving work by pivotally fitting a conveyor for taking the windrow of the pavement material on the ground to a front end of a self-traveling paving machine chassis freely to be tilted, and paving the material inside of the chassis with a screed in rear of the chassis. CONSTITUTION: A conveyor 26 for taking the windrow 64 heaped on the ground up is provided in a front end of a chassis 22 of a self-traveling paving machine 20 freely to be tilted in two dimensions in relation to the chassis. On the other hand, an inclination sensor 82 is provided at tip of the conveyor so as to semi- automatically control the tilting of the conveyor. A screed 24 is connected to a rear end of the chassis 22, and pushes and fastens the pavement material 32 fed from the chassis 22 so as to construct a road. With this structure, a paving machinery having the excellent working efficiency is obtained.

Pavement monitoring method for paving machine

Abstract: PURPOSE: To flatly finish the surface of pavement by a method wherein the result of measurement on the pavement thicknesses on a plurality of measuring points are graphed simultaneously on the screen of a display unit in accordance with the arrangement of the measuring points, and monitoring is made therewith for the pavement CONSTITUTION: Paving material B is laid and rolled with a screed 5 while a vehicle 1 is made to travel First and second distance sensors 21 and 22 measure the distances to the road surface and, at the same time, an odometer 27 measures the distance of travel, and all the measured results are outputted to a control device The pavement thicknesses on a plurality of points are obtained by computation with the control device, and a pavement thickness straight datum line is also obtained with the device by computation Then the screed 5 is so controlled as to pave the road on the pavement thickness straight datum line in accordance with the computed result Further, the obtained pavement thicknesses are graphed simultaneously on the screen of a display unit 36 in accordance with the arrangement of the measuring points COPYRIGHT: (C)1992,JPO&Japio

Effect of equipment and mix variables on surface shadows in asphalt concrete mats

Abstract: Surface irregularities causing a rough ride on an asphalt concrete pavement may be contributable to equipment related problems as well as to mix related problems. Problems relating to the laydown equipment can cause such irregularities as surface waves, ripples, tearing of the mat, screed marks, nonuniform texture and surface shadows. Surface shadows can be defined as areas of discoloration on the surface of the mat. In the past the surface shadows have been called auger shadows as they were thought to be related to overloading the augers on the paver with the asphalt concrete mix -- burying the augers. This study presents a discussion of the mixture variables as well as equipment variables which influence the presence and severity of surface shadows. The problem of surface shadows exists throughout the state of Texas. It is not restricted to any one type of mix, although mixture properties do influence the development of the phenomenon. A study of 11 hot mix projects in District 2 of the Texas State Department of Highways and Public Transportation is presented. This study examines equipment, construction and equipment variables. Based on the results of the study of the 11 selected projects in District 2, a field construction investigation was accomplished to create surface shadows "on demand" by varying selected parameters related to the paver and the paver operation. The field test project consisted of operations at three sites within Texas. The results of this evaluation are presented and analyzed. Suggestions are made by which to prevent or decrease the intensity and frequency of surface shadows based on the results of the field evaluation.

Effect of equipment and mix variables on surface shadows in asphalt concrete mats. final report

Abstract: Surface irregularities causing a rough ride on an asphalt concrete pavement may be contributable to equipment related problems as well as to mix related problems. Problems relating to the laydown equipment can cause such irregularities as surface waves, ripples, tearing of the mat, screed marks, nonuniform texture and surface shadows. Surface shadows can be defined as areas of discoloration on the surface of the mat. In the past the surface shadows have been called auger shadows as they were thought to be related to overloading the augers on the paver with the asphalt concrete mix -- burying the augers. This study presents a discussion of the mixture variables as well as equipment variables which influence the presence and severity of surface shadows. The problem of surface shadows exists throughout the state of Texas. It is not restricted to any one type of mix, although mixture properties do influence the development of the phenomenon. A study of 11 hot mix projects in District 2 of the Texas State Department of Highways and Public Transportation is presented. This study examines equipment, construction and equipment variables. Based on the results of the study of the 11 selected projects in District 2, a field construction investigation was accomplished to create surface shadows "on demand" by varying selected parameters related to the paver and the paver operation. The field test project consisted of operations at three sites within Texas. The results of this evaluation are presented and analyzed. Suggestions are made by which to prevent or decrease the intensity and frequency of surface shadows based on the results of the field evaluation.

Filling level meter for mixing machines

Abstract: A filling level meter for mixing machines, in particular for concrete, screed, mortar or the like, having a mixing container (12) and a mixing tool (14, 16) rotating in the mixing container comprises a flexible hollow body (22) which enters the interior of the mixing container (12) in the region of the highest filling level, and a measuring probe (36, 38, 40) which records an upwardly directed deformation of the hollow body.