Showing papers on "Mortar published in 1974"

Tests for the analysis of mortar samples

Abstract: Early mortars in North America are commonly a mixture of two or more ingredients: lime, sand, clay and portland Cement. By analyzing the mortar, identifying its components and measuring the ratio of in-gredients, it is possible to differentiate between seemingly simalar mortars. If we know the mortar-making practices of different periods a building may be dated with fair accuracy if the mortar is identified. Also, it is necessary to establish the ingredients of a mortar if it must be repro-duced for the restoration of a building. An easy method has been developed to analyze mortar samples on the field with a few simple utensils.

Additive for mortar and concrete

Abstract: The properties of mortar and concrete are improved by the addition to the fresh mortar or concrete of an aqueous dispersion of a plastic obtained by the emulsion polymerization of olefinically unsaturated monomers, and of a polycondensate of formaldehyde and an amino-s-triazine modified with sulfite or sulfonic acid. A well-balanced relation between the compressive strength, the tensile strength in bending, and the adhesion to aged and hardened mortar or concrete is thus obtained.

Steel-fibre-reinforced mortar: a technique for producing composites with uniaxial fibre alignment

Abstract: Synopsis A technique is described by which short steel fibres can be aligned parallel to the direction of tensile stress in mortar beams to be subjected to flexural loading. A combination of vibration and mechanical alignment enables the load carried by the beam to be doubled in comparison with that achieved by using vibration alone.

Method of grouting using specific mortar composition

Abstract: Novel aqueous non-hydraulic mortar compositions are disclosed comprising a film-forming, water-dispersible, room temperature cross-linkable polymer and a water-insoluble filler. Setting and grouting of ceramic tile by these compositions are also disclosed.

The tensile creep and fracture of desiccated concrete and mortar on water sorption

Abstract: The dynamic effects of water sorption on the strength reduction and the tensile creep of concrete and mortar are investigated. Moisture assisted crack growth is the major mechanism of tensile creep and/or, fracture of the desiccated material. Mechanisms of compressive creep of desiccated concrete on re-saturation with water, are discussed and compared with those of tensile creep.

Acid and heat-resistant mortars for cellular glass compositions and products therefrom

Abstract: Acid-resistant mortar compositions and selected products bonded therewith are provided wherein the mortar composition comprises a major portion of a cellular boro silicate glass powder, a silica sol, and a setting or hardening agent. Mortars of the invention are especially useful in bonding cellular glass bodies having a composition substantially identical to the boro silicate glass powder to provide bonded product arrays having excellent thermal shock characteristics.

Concrete containing sparingly soluble barium compounds

Abstract: In a concrete or mortar composition comprising cement or mortar, calcium sulfate and water, the improvement which comprises at least about 0.5% by weight of the cement or mortar of at least one sparingly soluble barium compound having a solubility product between 6.1 × 10.sup. -5 and 1.08 × 10.sup. -10 , e.g., barium oxalate, barium fluoride and/or barium silicate hydrate having a BaO:SiO 2 mole ratio of about 0.5 to 1.2.

Process for bonding a ferro-cement structure with fiberglass reinforced plastic

Abstract: A process for bonding a glass fiber reinforced plastic to a ferro-cement ucture to improve impact strength of the ferro-cement structure comprising the steps curing the ferro-cement mortar; acid etching the mortar on the side of the ferro-cement mortar to which the glass fiber reinforced plastic is to be bonded, rinsing the mortar, drying the mortar, applying a coat of adhesive to the mortar and attaching the glass fiber reinforced plastic to the bonded mortar surface The adhesive may be partially cured if desired

Process for accelerating cure and enhancing ultimate strength of prefabricated masonry structures

Abstract: A process for accelerating the cure and enhancing the ultimate strength of prefabricated masonry structures prepared using latex modified portland cement mortar com-prising (1) utilizing a portland cement mortar containing modifying amounts of a vinylidene chloride polymer latex and (2) substantially uniformly heating the non-cured pre-fabricated masonry structure to temperatures of from 110°F to 210°F under less than 80 percent relative humidity for a period of at least 4 hours.

Plastering mortar compsn. - contg. white fine lime, lime cement, cement or other hydraulic binder

Abstract: Mortar comprises lime cement, cement or other hydraulic binder and 0.5-8 wt. % (based on dry mortar) white fine lime with a particle size 50 mu. The mortar has a longer shelf like accelerated setting characteristics, and is used for manual or machine plastering of internal surfaces and facades. Compsn. may opt. contain cellulose ether 0.05-1.5 wt.%, plasticiser 0.01-0.2 wt.%, setting accelerator 0.05-2.0 wt. %, and mineral fibres 0.1-5.0 wt. %.

Reinforced concrete constructional elements - using mineral fibres in all or part of the cement or mortar, in addn. to steel

Abstract: A space-forming shaped part, esp. building elements of reinforced concrete, the novelty being that the cement-bonded mortar and concrete is partially or completely, i.e. uniformly throughout the cement-bonded matrix, reinforced with synthetic mineral fibres such as glass-, stone-, slag-, or carbon-fibres, impact toughness, and for improving the distribution of fissures or cracks. The fibres may be incorporated in the element as lost shuttering a pre-fabricated part, a facing mortar, or inclused in the cement or concrete mixt, pref. using fibres with adequate resistance against the alkaline media where required and/or treating the cement mixt with CO2 to reduce the alkalinity. The improved mechanical properties, including elongation, means higher permissible stresses and/or redn in size and wt of constructional elements, fire-resistance is also increased. As compared with concrete or mortar in which no fibres are used, the bending strength can be increased 3-8 times and the elongation at fracture increased up to 20 times; bending strengths up to 600 kp/cm2 are attainable and the better distribution of fissures means less environmental corrosion.

Reaction products in expansion test specimens of carbonate aggregate

Abstract: Detailed petrographic examinations and X-ray diffraction analyses were made of carbonate aggregates that had been tested by ASTM Methods C227 and C586. It was found that the most expansive mortar bars exhibited more external cracks and deposits of reaction products than did the less expansive bars. Any reaction rims were within the aggregate particles, and etching with various strengths of hydrochloric acid showed that they were negative. Rim- forming aggregates within the mortar bars appear in thin section to have undergone dedolomitization in the rim zone at the paste-aggregate interface. X-ray examination of the most expansive aggregates from these mortar bars failed to detect any brucite. However, comparison of the diffractograms generated by X-ray reflection from these reacted aggregates with diffractograms generated by the fresh, unused portions of these aggregates indicated that some type of dedolomitization reaction had occurred. The information obtained indicates that, under conditions found when testing rock for expansion by ASTM C586, the minerals of the hydrotalcite-sjogrenite mineral groups (complex magnesium carbonate hydroxides) can be the chief products of alkali dedolomitization near the surface of the test prisms of dolomite carbonate aggregate and that brucite can be the major dedolomitization product in the interior of the aggregate.

Adjustable rotary sensors for a self-restoring fluidic mortar support system

Abstract: An adjustable tripod support for the firing tube of a mortar is provided with a digital type of fluidic control system responsive to sensing means which detect a predetermined amount of the azimuth and elevation components of the recoil displacement imparted to the tube during firing. In response to such detection, the fluidic control system functions elevation and aziumth pistons which automatically restore the firing tube to the previously selected sighting inclination. The compressed air required by the fluidic control system is stored in an accumulator arranged to be automatically replenished by the discharge gases generated in the mortar tube during the firing thereof. As the firing tube is subjected to recoil displacement, the rotation of a chordally slabbed control shaft associated therewith serves to unblock one of a pair of sensing orifices for activating the control system to provide the required restoration movements of the firing tube. The combination of chordal edges and sensing orifices in each sensing means can be adjusted to provide a given deadband zone through which each control shaft must be rotated before the respective restoration movement is imparted to the firing tube.

Calcium sulphate anhydrite mortar

Abstract: Particulate anhydrite, of whose particles from about 2 to 6% by weight have a particle size greater than about 5 mm, from about 13 to 23% by weight have a particle size of from about 5 to 3.15 mm, from about 33 to 40% by weight have a particle size of from about 3.15 to 1 mm, from about 17 to 23% by weight have a particle size of from about 1 to 0.2 mm, and from about 17 to 33% by weight have a particle size less than about 0.2 mm, will provide a mortar developing high early strength without requiring an excessive amount of water. If the particles having a size less than about 0.2 mm are activatingly ground to increase their energy content to above the minimum possible under ambient pressure and temperature conditions, a particularly speedy initial rise in strength takes place.

Hydrostatic Extrusion of 60mm Mortar Tubes

Abstract: : Mortar tubes were successfully hydrostatically extruded from Inconel 718 proving the feasibility of the process. The yield strength of the 718 material was increased from 160 ksi to 240 ksi by the cold work induced by the extrusion process. A cost savings of about $400 per tube can be realized by hydrostatically extruding the mortar tubes close to finished size and thereby reducing the machining costs, rather than machining the tubes from forgings. Thus, it may be possible to economically use Inconel 718 and derive the benefits of the increased high temperature strength inherent in the material. As an adjunct to this project, an estimate was made of the potential savings for hydrostatically extruded gun steel mortar tubes compared to forged tubes. It is estimated that a savings of approximately $63 per tube would be possible.

Method of producing a brick wall facing

Abstract: The method of U.S. Pat. No. 3,096,195, incorporated by reference, is simplified by applying adhesive tape units, each of which consists of an assembly of a horizontal adhesive tape representing a horizontal mortar line for a course of brick to which are fixed vertical tapes spaced to represent vertical mortar lines between adjacent bricks. Apparatus is provided for making the tape units.

Porous lime mortar shaped bodies prodn - with metal expansion agent treated with anti corrosion agent

Abstract: The expansion agent, eg powdered Al metal, is heated with a dil. soln. of Na chromate or polyphosphate, N poly phenols or by adding the anti-corrosion agent in an amount of 0.01-8% based on the line content of the mortar. The mortar is allowed to expand and hardened by super heated steam.

Investigation of Polymer-Impregnated Brick Masonry

Abstract: Brick, brick prisms, and mortar specimens were impregnated with methyl methacrylate and polymerized by either a thermal-catalytic process or irradiation. Common brick and high-strength brick were used in the investigation. Compressive strength of polymer-impregnated common brick prisms increased 200% to 300% over the strength with a maximum of 18,088 psi, apparently the highest ever reported. Brick compressive strength and moduli of rupture, and mortar compressive and tensile strength also showed significant increases due to polymerization. The mortar-brick bond strength increased by more than 10 times. Thermal-catalytic polymerization produced higher strengths for common brick prisms and mortar specimens while polymerization achieved by irradiation produced higher strengths in the high-strength brick prisms. No significant differences were observed in the strengths of the brick polymerized by the two methods.

A Study of Cement and Concrete Correlation

Abstract: American specifications for portland cement require the crushing of mortar cubes for compressive strength of cement and the breaking of cylinder specimens for compressive strength of concrete. It has been assumed that there is a reasonable correlation of mortar and concrete strengths. This has been questioned. A preliminary study of sixty samples showed a significant correlation but indicated a very low order of confidence. A more extensive research was undertaken, which is reported in this paper. This research involved 42 job cement samples and twelve repetitions of a monitor cement. Each of the cements in mortar was subjected to the standard 3, 7, and 28-day strength tests, a repeat of the 28-day test, and two accelerated strength tests. The corresponding cements were tested in cylinders of ready-mixed concrete, sampled at both the batching plant and at the job site. Test specimens of these concretes were broken at seven days and at 28 days. Concrete from the job site was also tested after autogenous curing for two days. The same cements were used in two additional concrete batches at the research laboratory, the first using job mix proportions and the second using a standard formulation. Both batches for each cement used job sand and gravel. These latter concretes were tested after standard curing for 7 and 28 days, and other cylinders after accelerated curing under two different sets of conditions. Much information was obtained concerning the cements, the five mortar tests, the five concrete tests, and their many relationships—mortar/mortar, concrete/concrete, and mortar/concrete. Results were subjected to recognized statistical analysis. The paper includes 25 tables of data, 13 tables of processed information, and 18 figures. An evaluation of the testing laboratories indicated an acceptable level of competency; an analysis of the cement and concrete variations showed normal good levels of operation. These two factors provided limitations but also gave validity to the conclusions that have been drawn from the research.

Lightweight aggregate particle shape effect on structural concrete

Abstract: An exploratory investigation of six lightweight fine aggregates was conducted in an effort to extend the concept, developed with normal weight fine aggregates or sands, that one of the most important properties of fine aggregates is their particle shape features--angularity and texture as measured by loose void content. They affect mixing water requirements, water-cement ratio and, consequently, most of the strength characteristics of mortar having a constant cement-aggragate ratio. For a range of 10 percent in loose void content, compressive strength varied about 2000 psi (150 kgf/cm2). The lightweight fine aggregates were generally found to have high void contents and mortar mixing water requirements; therefore, they had lower strengths when compared to natural sand mortars. Further extending the results of this exploratory work, each of the lightweight fine aggregates, as well as that from a seventh source, and their coarse companions, were combined with the same natural quartzite, sand and gravel. Concrete was designed to contain 517 lb (234 kg) of cement, to have a 3 to 4 in. (8 to 10 cm) slump and no entrained air. Both compressive and flexural strength responded to these changes in mixing water content as a function of water-cement ratio. This concept leads to a more accurate design of structural lightweight concrete according to normal weight procedures.

Admixtures for mortar and concrete

Abstract: The admixture studied is whey, a by-product of the dairy industry. It consists of approximately 6% of dry extract (fat, lactose, albumen). It can be used as a retarder and increases the workability, thus leading to a saving of at least 5% cement. /TRRL/

Recycling discarded plaster moulds - by breaking into small lumps and heating before incorporation in plaster products, mortar, etc

Abstract: The plaster moulds are dried to 2 wt.% free water content, broken into pieces of 2-3 cm. size and ignited at 200 degrees C Max. to a crystal water content of around 2 wt.%. The product can be re-used in plaster materials, and esp. in pre-mixed mortar compsns. On mixing with water, the pieces rapidly break up into a fine powder. Prefd. pre-mixed mortar compsn. contg. the product also includes methyl cellulose or other sol. cellulose deriv.

Magnesium oxide incorporation to anhydrite binder - contg mortar for applying crack-free floors

Abstract: MgO is incorporated to anhydrite binder-contg. mortar compsns. used for surfacing and floor finishes, to prevent retarded hardening of mortar and/or swelling and shrinkage effectd leading to cracks in flooring. Pref. MgO amt. added is 0.5-1.5%, w.r.t. anhydrite MgO may be added to the dry anhydrite or to synthetic anhydrite, already during neutralisation of H2SO4 residues present.