Showing papers on "Screed published in 2003"

Wire mesh screed

Abstract: This invention relates to screed methods and building panels. According to the invention there is provided a construction panel comprising two outer wire mesh members and a middle member secured therebetween. The wire mesh members may have a plurality of V-shaped impressions along their length which serve as a built in visual and mechanical screed for finishing the panel with shotcrete or plaster. Alternatively, the wire mesh members may have a clipped-on-screed member attached thereto which serves as a visual and mechanical screed for finishing the panel. The middle member may comprises a composite of alternating layers of wire trusses and polystyrene foam. The middle member may be secured in a compressed state and released after attachment to the wire mesh members.

Concrete screed with vibration isolation

Abstract: A vibratory concrete screed includes a vibration isolation system that minimizes the transmission of vibrations to the operator under normal operating conditions, but becomes more rigid during screed control forces applied to the blade through the isolation system when the operator applies greater forces to the operator handle. The system includes low durometer elastomer vibration isolators isolating the operator handle from the vibration exciter and screed blade in a manner that limits vertical compressive movement of the isolators, yet permits substantially greater horizontal shear movement to effectively isolate the operator from vibration. The isolator mounting arrangement also includes retainers that engage the isolator to limit the amplitude of horizontal shear movement when the operator applies a greater control force to the operator handle.

Multi-story concrete slab construction

Abstract: A system and method of constructing multi-story buildings having poured-in-place concrete floors for the upper floors, wherein a set of lower posts is erected, the lower posts having horizontal upper plates on their upper ends each with a centrally disposed aperture. Decking is supported by horizontal beams and defines a form to receive the concrete. The upper plates are masked and concrete is poured and screeded using the upper plates as screed guides, such that the upper surface of the concrete is generally flush with the upper surface of the upper plates. After removal of the masking, a set of upper posts having lower plates with centrally disposed pins are mounted atop the lower posts with the pins inserted into the apertures. The lower plates and upper plates are then welded to joint the lower and upper posts. The cycle is repeated for additional floors.

Adjustable screed system

Abstract: A mechanical linkage having a geometry designed to substantially hold the plane of a main screed and the plane of an extension screed at a generally constant relative angle with respect to one another through a predetermined range of screed depth adjustments. The linkage is configured to allow the extension screed to be raised and lowered by an amount sufficient to compensate for angle of attack and elevation changes in the main screed. In particular, the linkage compensates for the effect of the radial distance differences from the axis of rotation of tow bars of the main screed and extension screed as the main screed pivots with respect to the tow point of the tow bars for different asphalt mat depths. An alternate embodiment includes actuators, together with sensors, for sensing the position of the extension screed with respect to the main screed and automatically compensating for changes in main screed position to properly orient the extension screed with respect to the main screed.

Apparatus for screeding concrete and other materials

Abstract: Apparatus for screeding concrete and other materials includes a primary support and a secondary support adjustably slidably movable on the primary support to raise or lower an elongated screed guide member The secondary support includes a receptacle for holding the elongated screed guide member Surface engaging support structure is provided at the lower end of the apparatus to disperse downwardly directed forces

VOC- und SVOC-Emissionen aus Fussbodenaufbauten und den dafür verwendeten Materialien

Abstract: VOC- and SVOC-emissions from materials for flooring installation (primer, screed, adhesive, floor covering) were measured by means of emission test chambers and cells over a time period of at least 28 days at 23°C, 50% relative humidity and an area specific air flow rate of q=1.25 m 3 /m 2 .h. Single components were tested in comparison to three complete structures (same concrete, primer, screed, adhesive) with different types of floor covering (PVC, carpet, linoleum). Sorption into concrete/screed and different sealing by the flooring materials affected the emissions from the complete structures. The complete structures with linoleum and PVC showed the same types of emission and emission rates as the individual flooring materials themselves. Emissions from the carpet-covered structure resulted also from the lower layers. In all cases emissions from the complete structures were lower than the sum of emissions from the single components. For two adhesives the formation of secondary emissions (aldehydes and organic acids) was observed starting after the standard testing time of 28 days.

Road paver-finisher with automatic control of the height of the transverse augers with respect to the screed

Abstract: of EP0774542A road paver-finisher having a screed unit of the semi-floating type in front of which operates a system of augers for transverse distribution of the mixture to be laid, has the auger(s) (15) mounted on a sub-frame (32) equipped with arms (34) that remain approximately parallel to the arms (16) of the screed (11), the front ends (35) of the arms (34) of the sub-frame (32) being mounted on the tractor (10) at their centers of rotation (36), the latter always being situated very close to the centers of rotation and traction (18) of the front end (17) of the arms (16) of the screed (11), the upward and downward movement of the augers taking place as a motion of rotation around the centers (36) by means of actuators, for example hydraulic pistons (40') mounted on the tractor (10) that engage on the sub-frame (32) or on the arms (34)

Paving screed for a paver

Abstract: The invention relates to a paving screed for a paver, with a basic screed and with at least one lateral extendable screed part which is connected to the basic screed via hydraulically actuable tensioners. The height of the extendable screed part can be adjusted via a height setting device which comprises vertical spindles which are coupled to the extendable screed part and are held on the basic screed rotatably relative to the latter. The spindles are adjustable via a common drive motor, it being possible, as a result of the actuation of the drive motor, to trigger a release of the hydraulically actuable tensioners for the duration of actuation. The extendable screed part is also connected to the basic screed via spring-biased screws.

Combined sand strike-off mechanism

Abstract: The utility model discloses a combined sand strike-off mechanism which consists of a flat scraper and a screed. The flat scraper is positioned on the upper end, and the screed is installed on an upright post through a rotating shaft, while the lower end of the screed is provided with an adjusting bolt. The utility model is characterized in that the back of the screed is connected with a cylinder which is provided with a dust-preventing board and can drive the flat scraper to conduct the falling sand strike-off, and a hob is provided on the sand feeding type, which conducts sand strike off for the sand feeding type. The combined sand strike-off mechanism can complete a plurality of super large and high castings under the circumstances of restriction by the tooling equipment, thereby exerting an extension effect. Moreover, the practice has proved that the utility model has quite remarkable advantage and can completely meet the technological requirements. The utility model is convenient for installation, simple in maintenance, thereby guaranteeing the production quality and improving the forming rate.

Abrasion resistance of fibre reinforced concrete floors

Abstract: This thesis focuses on the investigation of the abrasion resistance of fibre reinforced concrete floors at both the macro and micro levels. A literature review of the available literature concerning subjects allied to the current project is included. This highlights themes relevant to wear mechanisms and the factors influencing it: factors that affect the abrasion resistance of concrete and several test methods for assessing it; and the historical development of fibres and the properties of different fibre types and their influence on concrete. Three accelerated abrasion testers were compared and critically discussed for their suitability for assessing the abrasion resistance of concrete floors. Based on the experimental findings one accelerated abrasion apparatus was selected as more appropriate to be used for carrying out the main investigations. The laboratory programme that followed was undertaken to investigate the influence of various material and construction factors on abrasion resistance. These included mix variations (w/c ratio), fibre reinforcement, geometry, type and volume, curing method and superplasticizing agents. The results clearly show that these factors significantly affected abrasion resistance and several mechanisms were presumed to explain and better understand these observations. To verify and understand these mechanisms that are accountable for the breakdown of concrete slabs, the same concrete specimens that were used for the macro-study, were also subjected to microstructutural investigations using techniques such as Microhardness examination, Mercury intrusion porosimetry and Petrographic examination. It has been found that the abrasion resistance of concrete is primarily dependent on the microstructure and porosity of the concrete nearest to the surface. The feasibility of predicting the abrasion resistance of fibre reinforced concrete floors by indirect and non-destructive methods was investigated using five methods that have frequently been used for assessing the quality of concrete. They included the initial surface absorption test, the impact test, ball cratering, the scratch test and the base hardness test. The impact resistance (BRE screed tester) and scratch resistance (Base hardness tester) were found to be the most sensitive to factors affecting abrasion resistance and hence are considered to be the most appropriate testing techniques. In an attempt to develop an appropriate method for assessing the abrasion resistance of heavy-duty industrial concrete floors, it was found that the presence of curing/sealing compound on the concrete surface at the time of accelerated abrasion testing produces inappropriate results. A preliminary investigation in the direction of modifying the Aston accelerated abrasion tester has been carried out and a more aggressive head has been developed and is pending future research towards standardisation.

Development of a screed to detect and measure segregation of hma pavements

Abstract: This Innovations Deserving Exploratory Analysis (IDEA) project developed and tested an infrared sensor-based screed attachment for asphalt paving equipment to monitor temperature differentials as a method for detecting and measuring segregation during construction. The prototype system consists of a transverse line of infrared sensors, signal conditioners, computer data acquisition system, and a global positioning system (GPS). The system is capable of continuously monitoring temperature differentials during construction. Real time transverse temperatures are plotted on a computer screen for use by the paving crew. The software produces a summary of potentially segregated areas by level of segregation (i.e., low medium, and high) as well as the number of paver stops over one minute for use by the state agency. Preliminary testing with the system on existing pavement surfaces shows that the system can adequately evaluate the transverse temperature differential. The low budget GPS is found to be reasonably accurate over multiple runs for locating pavement anomalies. The software is easy to use and automatically prepares the agency report that locates all non-uniform transverse temperature areas.

Material alignment for compaction

Abstract: A member, screed and method for realigning material and compacting. A material realigning member is provided including structure for moving at least a first portion of a depth of a quantity of material laterally from an initial position thereof and then at least a second portion of the depth of the quantity of material back towards the initial position. In this fashion, aggregate particles may be moved in three horizontal directions, e.g., a direction of travel by a roller waveform, and both lateral directions by the invention, to realign material and allow for improved compaction.

Laying-leveling machine

Abstract: PROBLEM TO BE SOLVED: To provide a laying-leveling machine which is simple in structure without provision of auxiliary wheels, and stably carries out laying-leveling work and deadheading. SOLUTION: According to the laying-leveling machine, an automotive vehicle 1 comprises a traveling crawler 9, and a lower screw 4, a lower screed 5, an upper screw 7, and an upper screed 8 are arranged behind the traveling crawler 9. Further, an upper hopper 3 and a driver seat 22 are arranged behind the traveling crawler 9. Then, an operating oil tank 23, a water tank 16, and a power unit 13 are arranged in front of the lower hopper 2, which cooperatively function as a counterweight. Therefore, by virtue of load working behind the traveling crawler 9 and the counterweight in front of the lower hopper 2, the center of gravity of the laying-leveling machine A is located in the vicinity of the center of the traveling crawler 9, which allows stable maintenance of weight balance of the machine, to thereby achieve good finish on a pavement surface.

Invert concrete building method and invert concrete building device

Abstract: PROBLEM TO BE SOLVED: To provide an invert concrete building method which is implemented by using a simple device and achieves concrete building with good efficiency and high quality, and to provide an invert concrete building device. SOLUTION: Concrete placing step, a molding step by using a slip form, and a finishing step are carried out in parallel by using the invert concrete building device 1 which is divided to separate carriages 2, 3 and 4, even if working speed and moving timing are different from those in each step. Then the carriages 2, 3 and 4 can travel through a lower portion 16 along a tunnel inner wall surface by means of traveling wheels 5, and therefore the setting and removal work of rails is dispensed with, to thereby save cost and labor required for the work. Further the slip form 3 is employed for molding the invert concrete 18, and therefore leveling work with a screed by an operator is simplified. Furthermore final finishing is conducted by the operator, and therefore the visual checking and correction of a finished condition by the operator is carried out on the spot, which improves the quality and working efficiency of the building. COPYRIGHT: (C)2005,JPO&NCIPI

Counter weight device for paving machine

Abstract: PROBLEM TO BE SOLVED: To secure good body balance and steering performance of a paving machine with a screed device during travel and improve body tractive force during construction SOLUTION: A counter weight 13 movable forward or backward and a weight driving chain 19, sprockets 17, 18 and a hydraulic motor for moving the counter weight are arranged in a space inside a feeder conveyor 5 The counter weight can be moved forward or backward to be set at the gravity center position adequate for travel or construction working conditions

Damper control device of asphalt finisher

Abstract: PROBLEM TO BE SOLVED: To prevent breakage of a damper motor in cold time by inhibiting the drive of a damper device until a screed device is enough heated SOLUTION: A switch 23, a temperature detecting sensor 24, a relay 25 and a screed heating device 26 are connected to a controller 30 An A contact 28 of the relay 25 is interposed between a damper driving switch 27 and a solenoid 21 of a damper driving solenoid control valve When a screed plate does not reach a fixed temperature, the A contact 28 of the relay is in the off state, so the solenoid 21 is not excited, so that the damper device is not driven On the contrary, when the screed plate is heated more than fixed, the A contact 28 of the relay is turned on, so that when the damper driving switch 27 is turned on, the solenoid 21 is excited to drive the damper device COPYRIGHT: (C)2003,JPO

Properties of High Performance Materials Based on Calcium Sulfoaluminate Cement

Abstract: This research concludes that a wide range of innovative building materials can be developed using sulfoaluminate cement, high early strength concrete, self leveling topping mortars and high performance glass fiber reinforced composites. The above materials are based on three main properties exhibited by calcium sulfoaluminate cement: rapid formation of etteringite, expansive property of etteringite, and low alkalinity of the pore solution of the cementitious matrix. Other materials under development include: self levelling screed with limited curling, fire resistant materials, and materials including large amounts of industrials by-products.

Construction method for elastic paving body

Abstract: PROBLEM TO BE SOLVED: To provide a construction method for an elastic paving body capable of constructing the elastic paving body suitable specially for a vehicle track made of fibrous rubber (short-fibrous rubber) by site operation. SOLUTION: A blend process obtaining elastic paving compound 30 mixing a predetermined binder 33 with aggregate having the fibrous rubber 31 as a main ingredient, the first leveling process tentatively leveling the elastic paving compound 30 in thickness of 3 to 100 mm thicker than a target construction layer thickness in an unsolidified state on a predetermined substrate 2, a pressing process pressing the tentatively leveled elastic paving compound 30 within a range of the thickness not higher than the height of the forward end in the direction of movement of a screed at the target construction layer thickness or above and the second leveling process finishing the pressed elastic paving compound 30 in the target construction layer thickness by the screed 44 are carried out. COPYRIGHT: (C)2005,JPO&NCIPI

Procedure for screeding concrete walls using two thin walled 3/4 inch conduit linarly placed three feet from the floor and ceiling as screed guide after shotcrete concrete emplacement

Abstract: The usefulness of placing two guide tubes on the wall to be screeded is that it turns a high skilled process (free hand depth management of wall grout) into a very unskilled process: Sawing concrete across two parallel equal level guides.

Use of glass waste in cement screed compositions

Abstract: A cementitious screed which comprises recycled glass waste. The screed may comprise calcium sulphate, portland cement, high alumina cement, calcium sulpho-aluminate cement, limestone powder, silica fume, pulverised fuel ash or a combination of these. The screed may further comprise a retarder, an accelerator, a plasticiser or an organic polymer.