Showing papers on "Mortar published in 1973"

Cement paste and concrete

Abstract: This paper outlines the current state of knowledge as regards the chemical and physical aspects of the structure of hardened cement paste, then relates the properties of shrinkage, inelastic behavior, and creep to structure. Some significant recent developments in materials for concrete production are presented. New materials include (a) two types of matrices: expansive cement and regulated set cement, (b) two types of reinforcements: fiber reinforcements and ferrocement, and (c) two types of polymeric additions: polymer latex modified mortar and polymer impregnated concrete. Artificial aggregates including possible use of waste products and special techniques for preparation of extremely high strength cement pastes are also discussed.

Mortar with variable vent for adjusting velocity of a single charge cartridge

Abstract: A variably adjusted vent communicates with the interior of a mortar tube. adjusting the vent setting, the velocity of a single charge cartridge can be varied. In one embodiment of the invention, the vent discharge is exhausted below the base plate of the mortar to stabilize the mortar during firing.

Parachute Mortar Design

Abstract: Mortars are used as one method for ejecting parachutes into the airstream to decelerate spacecraft and aircraft pilot escape modules and to effect spin recovery of the aircraft. An approach to design of mortars in the class that can accommodate parachutes in the 20- to 55-foot-diameter size is presented. Parachute deployment considerations are discussed. Comments are made on the design of a power unit, mortar tube, cover, and sabot. Propellant selection and breech characteristics and size are discussed. A method of estimating hardware weights and reaction load is presented. In addition, some aspects of erodible orifices are given as well as comments concerning ambient effects on performance. This paper collates data and experience from design and flight qualification of four mortar systems, and provides pertinent estimations that should be of interest on programs considering parachute deployment.

Portable hopper apparatus for supplying a dry mortar mix

Abstract: There is disclosed an apparatus for supplying a dry mortar mix comprising containers with a gate valve at one end and a hook at the opposite end and a support for holding at least two such containers with the gate valve lowermost and the hook uppermost. The support is placed at a construction site and the containers are filled at a plant with dry sand and cement mortar mix and are delivered to the construction site by truck. Installation of the containers and the support is done by a crane. Empty container(s) are removed and replaced by full one(s). Other container(s) can be tapped in the meantime to ensure that the supply of mix is continuous.

The effects of adhesive bond between coarse aggregate and mortar on the physical properties of concrete

Abstract: THE PURPOSE OF THIS INVESTIGATION WAS TO EXAMINE THE CONTRIBUTION MADE BY THE ADHESION BETWEEN COARSE AGGREGATE AND MORTAR TO THE COMPRESSIVE STRENGTH AND OTHER PHYSICAL PROPERTIES OF PLAIN CONCRETE. TO ELIMINATE ADHESIVE BONDS WITHOUT AFFECTING THE POTENTIAL MECHANICAL INTERLOCK OR PHYSICAL KEYING BETWEEN THE AGGREGATE MATERIAL AND THE MORTAR, A SILICONE RELEASE AGENT WAS EMPLOYED. (A)

Cement asphalt ballast grout composition for track

Abstract: A cement asphalt ballast grout composition comprising cement, an asphalt emulsion, calcium sulfoaluminate hydrate-forming mineral, an electrolyte, a thickener and a foaming agent is excellent in the workability of mortar and in the property of hardened mortar, and is suitable as a cement asphalt ballast grout composition for directly joining-type track.

The Viking mortar - Design, development, and flight qualification.

Abstract: Approximately 25,400 ft above the local surface of Mars, a radar height sensor fires the Viking mortar, which ejects a 53-ft D sub o disk-gap-band (DGB) parachute. The parachute decelerates and stabilizes the Viking lander sufficiently for the terminal engine system to take over and effect a soft landing. The general design and environmental requirements for the mortar system are presented; various illustrations of the mortar components and how the mortar system functions also are presented. Primary emphasis is placed on manufacturing, developing, and qualification testing of the mortar system.

The influence of porosity and partial drying on the properties of polymer-impregnated mortar

Abstract: Three mortar mixes of widely differing porosities were impregnated with three vinyl monomers and methanol. The monomers were polymerized thermally using a free radical initiator. Specimens of one of the mortar mixes were dried to different relative water vapor pressures prior to impregnation with either methyl methacrylate or styrene. The compressive strength was determined in all cases and the strains in the partially dried specimens were recorded throughout the processing cycle. The compressive strength of the impregnated mortars was found to be a function of both porosity and the properties of the matrix and polymer. Length changes during processing were dependent on the degree of drying. Maximum swelling in monomer occurred in specimens stabilized at intermediate relative humidities. /ACI/

The effect of different test procedures upon the indicated strength of concrete blocks in compression

Abstract: Synopsis Although the use of loose fibre-board caps with single blocks may increase the variation within a set of results when compared with mortar capping, the amount will depend largely upon the skill and experience of the mortar-capping operative. From an economic viewpoint, the board-capped single block specimen offers several advantages, and the sample size may be adjusted to give the required level of accuracy to the determination of block strength. The relationship between the results of tests on mortar- and board-capped specimens may be calculated, and both forms of test related directly to the performance of concrete block work walls.

Method for preparing brick panels

Abstract: An improvement in the process for preparing prefabricated building panels by arranging a plurality of bricks on a substantially horizontal bed and filling the spaces between the bricks with a flowable mortar wherein the improvement comprises using a vinylidene chloride polymer latex-modified portland cement mortar composition as the flowable mortar, then applying pressure along the panel sufficient to compress the mortar in an amount of from about 1 to 2 millimeters substantially uniformly throughout the panel, wherein such pressure is applied prior to initial setting of the mortar.

Pressurized mortar pot apparatus

Abstract: A two-part pressure vessel includes an upper section containing a pressure tank, which is secured to a cylindrical lower section by a clamp and flange arrangement. A charge of mortar is placed in the lower section, after which the pressure vessel is assembled. The vessel contains a reciprocable piston that is carried by the upper section, and which is driven toward the mortar charge by compressed air drawn from the pressure tank. The lower section has a mortar discharge outlet, which is connected to a trowel or nozzle by a flexible conduit made of hose or other flexible material. Mortar is withdrawn from the pressure vessel upon demand by operating a valve controlling the flow of compressed air to the region behind the piston, the pressure acting on the piston being regulated to ensure even feeding of the mortar. The piston rod has a bleed passage extending therethrough, whereby air trapped beneath the piston can be released to help ensure even feeding of the mortar, and a relief valve is provided to relieve air pressure behind the piston when desired.

Deterioration of 249 bridge decks, with discussion

Abstract: A STUDY OF 249 BRIDGE DECKS BUILT IN 1966 IN PENNSYLVANIA WAS INITIATED IN AN ATTEMPT TO LEARN THE EXTENT OF DETERIORATION AND TO ESTABLISH THE RELATIVE IMPORTANCE OF FACTORS COMMONLY ASSOCIATED WITH DETERIORATION. THREE MAJOR FORMS OF DETERIORATION WERE CONSIDERED: SPALLS AND FRACTURE PLANES; SURFACE MORTAR DETERIORATION, INCLUDING WEAR BY TRAFFIC AND THE GENERAL DISINTEGRATION OF WEAK MORTAR; AND CRACKING, INCLUDING TRANSVERSE, LONGITUDINAL, AND DIAGONAL. INFORMATION FROM BLUEPRINTS, CONSTRUCTION AND MAINTENANCE RECORDS, AND INDIVIDUAL CONTRACTORS WAS GATHERED CONCERNING 32 FACTORS RELATED TO DETERIORATION. FRACTURE PLANES AND SPALLS, THE MOST SERIOUS FORM OF DETERIORATION FROM A REPAIR COST STANDPOINT, WERE FOUND ON 22 PERCENT OF THE DECKS AND IN MANY DIFFERENT POSITIONS ON THE DECKS. FROM THE STANDPOINT OF SKID RESISTANCE, WEAR IS THE MOST SERIOUS FORM OF DETERIORATION. NINETY-FIVE PERCENT OF THE DECKS EXHIBITED SURFACE MORTAR DETERIORATION, WITH 97 PERCENT OF THE AFFECTED AREA ATTRIBUTED TO WEAR AND ONLY 3 PERCENT ATTRIBUTED TO DISINTEGRATION OF WEAK MORTAR. ABOUT 6.7 MILES OF CRACKS WERE ENCOUNTERED ON THE 21.5 LANE-MILES OF DECK SURFACE OBSERVED. BY NUMBER AND LENGTH, TRANSVERSE CRACKS OCCURRED MORE FREQUNETLY AND, IN ESSENTIALLY EVERY CASE, OCCURRED DIRECTLY OVER THE TRANSVERSE REINFORCING BARS. IT IS RECOMMENDED THAT PROVISION OF SUFFICIENT CONCRETE COVER BE MADE ON A BASIS SIMILAR TO THAT FOR SLAB THICKNESS OF HIGHWAY PAVEMENTS. ALSO, IT IS RECOMMENDED THAT FLEXURAL STRENGTH REQUIREMENTS FOR BRIDGE DECK CONCRETE BE INCREASED TO 700 PSI.

Hydraulic mortar - contg hydraulic binder comminuted pumice with high proportion of fines and surfactant

Abstract: Mortar contg. granular and powdered pumice with high proportion of particles below 90 mu m or 63 mu m can be readily foamed and worked, and has good mechanical strength and heat-insulating props.

Mortar compsn. for corrosion preventing coating in water pipes - contg. hydraulic cement and organic binder in organic solvent

Abstract: Mortar compsn. for the formation of corrosion-preventing coatings on steel surfaces in contact with water, consisting of a suspension of a hydraulic cement in a liquid, is improved in that the liquid is a soln. of an organic binder in an organic solvent hich solidifies upon application onto the surface to be protected.

High strength mortar for pavements - contg anhydrite and special cement

Abstract: The mortar contains synthetic anhydrite binder and special cement, (C, A-free) esp. in a ratio of 12:1-12:18. Gas evolution during setting is avoided.

Aggregate grading and the internal structure of concrete

Abstract: It is shown that there are many gradings for concrete aggregate that can be considered as optimum for one purpose or another. In addition to the behavior of the concrete in the frash as well as in the hardened state, visual inspection of the internal structure of concrete reveals whether the grading used is close enough to the desired optimum. A method, adopted from a procedure used in petrography, is presented for such evaluation of the structure of concrete. This is based on the measurement of the intercepts of mortar layers among coarse aggregate particles in the finished concrete. Various kinds of concretes are analyzed by this method. The results indicate that there exists a needed minimum value for the average mortar layer intercept below which the workability of the concrete is inadequate; this needed minimum mortar intercept is dependent on several factors such as the method of compaction and the grading of the sand; and the minimum value seems to be independent of the particle shape of the coarse aggregate. The effect of the particle shape of coarse aggregate on the grading optimum is also discussed. Based on this, two methods for measuring the angularity of the particles are recommended. Finally, internal structures of concretes made with continuous gradings and comparable gap gradings are contrasted.

Process for shaping components made of concrete or mortar

Abstract: Process and device for shaping components made of mortar or concrete in which the temperature of the concrete is reduced to a value which makes it possible to freeze concretes and mortars.

Durability of Fiber Glass-Portland Cement Composites

Abstract: THE DURABILITY OF FIBER GLASS PROTECTED WITH EPOXY-PHENOL COATINGS IN PORTLAND CEMENT MORTAR WAS INVESTIGATED. AGING AND STRESS CORROSION TESTS TO 2 YEARS, INDICATE NORMAL FIBER GLASS MUST BE PROTECTED COMPLETELY WITH A PINHOLE FREE COATING TO WITHSTAND ALKALI ATTACK OVER LONG PERIODS, AS WELL AS A COATING WHICH WILL MIGRATE INTO THE MORTAR TO AFFORD GOOD BOND STRENGTH. /AUTHOR/

Low-density mortar - with improved heat insulating properties for use with low-density bricks or sheet

Abstract: The mortars contain (A) 1.4-1.6 pts. polystyrene foam particles, (B) 40-50 pts. cement, (C) 5-9 pts. lime, (D) 15-20 pts. trass or stone flour, (E) 5-20 pts. fine additives, e.g., slat flour, pumice, etc., (F) 0.05-0.07 pts. hydroxyethyl cellulose and (G) 0.05-0.07 pts. metal soap. (A) pref. consists of spherical particles of 0.3-2.5 mm dia. The mortars have improved heat insulating props. comparable with those of low density bricks or sheets, and prevent moisture condensation and formation of stain patterns after plastering over.

Mortar compsn - producing easily cleanable pore-free surfaces and suitable for casting with negative moulds

Abstract: Compsn consists of sand, granular aggregate (sand, marble etc), finely ground aggregate mineral and an additive) of PVAc powder together with a conventional plasticiser which is compatible with PVAc powder, gelling the mixt and defoaming.

Mortars for zirconia refractories

Abstract: The composition was developed for a mortar based on zirconium dioxide and orthophosphoric acid intended for laying zirconia refractories. The filler should be stabilized ZrO2 powder of a particle size below 0.5 mm with 10% monoclinic fine-grain ZrO2 mixed with orthophosphoric acid added in the proportion of 2–4% in terms of P2O5.