Abstract: A method for manufacturing a cementitious composition comprisinga) uniformally fluidising in a container, particles of a substantially dry powdered cementitious composition by creating aerial motion of the particles by rotational motion perpendicular to the fall of the particles,b) at the same time uniformally spraying the particles with 0.1 to 10 parts by weight (per 100 parts of cementitious composition) of water, optionally containing a cement admixture, andc) mixing the particles and the water intensively by shearing forces.
Abstract: In an operation wherein a gaseous stream, such as an air stream, is contacted with a liquid selective solvent for a component of the gaseous stream for the removal of said component from the gaseous stream, improved results are obtain, particularly in a direct gas-liquid countercurrent contacting operation, by employing a liquid selective solvent which has a viscosity of less than about 30 centipoises at 77.degree. F. Suitable such solvents include diethyl phthalate, dioctyl phthalate, dioctyl adipate, acetyltributyl citrate and diisohexyl phthalate, particularly blends or mixtures thereof.
Abstract: A chloride-free admixture for use as a cold weather (e.g., 13.degree. F. to 40.degree. F.) concrete set accelerator. The admixtures comprise;1) at least one soluble inorganic salt having freezing point depressant properties,2) at least one water reducing dispersant, e.g., superplasticizer,3) at least one inorganic early set and strength accelerator, and optionally,4) at least one inorganic set accelerator.
Abstract: A polymeric composition which reduces the loss of flowability of a cementitious composition comprises at least one polymer as a salt thereof having the form of a copolymer of(a) a maleic anhydride half-ester with a compound of the formula IRO(AO).sub.m H (I)where R is a C.sub.1-20 alkyl group, A is a C.sub.2-4 alkylene group and m is an integer from 2-16; and(b) a monomer having the formula IICH.sub.2 .dbd.CHCH.sub.2 -(OA).sub.n OR (II)where n is an integer from 1-90.In a preferred embodiment, there is present a polycarboxylate salt which is at least one polymer or copolymer comprising at least one of the monomers acrylic acid, methacrylic acid, maleic anhydride, maleic acid and maleic acid monoester, polymer and polycarboxylate salt being blended in the proportion of 0.1-10 parts of weight of polymer per part of polycarboxylate salt.Cementitious compositions such as concrete in which such polymeric compositions are included maintain their slump properties.
Abstract: The invention relates to organic copolymers in free acid or salt form with recurring units of formula I ##STR1## in which R is an alkylene radical with 2 to 6 carbon atoms,R.sub.1 is a C.sub.1-20 alkyl-, cycloalkyl- or phenyl group,x, y and z are numbers from 0.01 to 100,m is a number from 1 to 100 andn is a number from 10 to 100,with the provisos, thati) the ratio of x to (y+z) is from 1:10 to 10:1 inclusive,ii) the ratio of z to y is from 3:1 to 100:1, andiii) m+n=15-100.The products of the invention are excellent superplasticizers and can be used as additives to cementitious mixes.
Abstract: An apparatus and a process for mixing water from a pressurized source and an additive or admixture for a cementitious composition in a mixing chamber comprising introducing, in the form of a jet, water under a first pressure, which is above atmospheric pressure, and introducing the additive under a second pressure between atmospheric pressure and the first pressure, the amount of the additive that is introduced to the mixing chamber being controlled by means regulated by the pressure of water.
Abstract: A shotcrete gun having a rotatable multichamber rotor, with a top feed hopper for receiving a dry concrete mixture in a chamber, and a bottom outlet pipe for discharging the dry concrete mixture from the chamber. The outlet pipe having a compressed air connector for connection to a compressed air source. The upper surface of the drum rotor adjoins a gasket having one or more openings fixed to a clamping plate. The lower surface of the drum rotor adjoins a gasket which is fixed to a base plate. The hopper and the outlet pipe being spaced such that a chamber which communicates directly with the hopper can be moved so that it no longer communicates with the hopper but communicates with the outlet pipe. The clamping plate has a compressed air connector for blowing the dry mixture out into the outlet pipe.
Abstract: An admixture for ultra-dry-mix concrete is disclosed containing one or more varieties of cement dispersing agents (A) selected from a group consisting of lignosulfonates, oxycarboxylates and polycarboxylates, and in addition, containing one or more varieties of nonionic surface-active agents (B) selected from a group consisting of polyoxyalkylene alkylaryl and alkyl ethers with a hydrophilic-lipophilic balance (HLB-value) of 8 to 17.
Abstract: A shotcrete gun having a rotatable multichamber rotor, with a top feed hopper for receiving a dry concrete mixture in a chamber, and a bottom outlet pipe for discharging the dry concret mixture from the chamber. The outlet pipe having a compressed air connector for connection to a compressed air source. The upper surface of the drum rotor adjoins a gasket having one or more openings fixed to a clamping plate. The lower surface of the drum rotor adjoins a gasket which is fixed to a base plate. The hopper and the outlet pipe being spaced such that a chamber which communicates directly with the hopper can be moved so that it no longer communicates with the hopper but communicates with the outlet pipe. The clamping plate has a compressed air connector for blowing the dry mixture out into the outlet pipe, and at least three pressure cylinders in order to press the gasket against the drum rotor. Means are provided for maintaining the pressure in the cylinders proportional to the pressure in the outlet pipe.
Abstract: A protective coating for application to steel reinforced concrete structures, comprising a liquid composition of elastomeric polymeric material having electrically conductive particulate matter evenly dispersed therein. A cathodic protection system embodying the coating comprises a moisture impervious membrane of elastomeric polymeric material having electrically conductive particulate material evenly dispersed therein, an electrically conductive grid embedded in the membrane or contiguous thereto, and direct current means connecting the grid electrically with the reinforcing bars.
April 10, 1989
Date of Patent:
December 3, 1991
Thomas M. Callaghan, Vallabhdas M. Pasta, Vasant D. Kale, Charles A. Bruce
Abstract: A method of reclaiming leftover ready-mix concrete comprising the steps of:(1) retarding the hydration of the unused portion of concrete returned from a job site; and(2) after the desired retarded period adding a hydration acceleration agent to restore the concrete to a settable state.
March 8, 1990
Date of Patent:
October 23, 1990
Gregory S. Bobrowski, Gregory C. J. Guecia, David A. Lupyan, Frederick D. Kinney
Abstract: A semi-permeable membrane .[.which comprises.]. .Iadd.having high permeability characteristics is disclosed. This may comprise .Iaddend.either(i) a copolymer of acrylonitrile and at least one ionic or ionizable monomer, or(ii) a copolymer of acrylonitrile, at least one ionic or ionizable monomer, and at least one non-ionic and non-ionizable monomer, or(iii) a mixture of at least two copolymers as defined under (i) and/or (ii), or(iv) a mixture of at least one copolymer as defined under (i) and/or (ii), and at least one copolymer of acrylonitrile and at least one non-ionic and non-ionizable monomer, the ionic or ionizable monomer units representing from 1 to 80 mole % of the monomer units in one of said copolymers, and representing from 1 to 50 mole % of the monomer units in the membrane, said membrane having a degree of salt rejection of less than 1% and a permeability to water of more than 100 liters/day.m.sup.