Abstract: An early strength hydraulic cement comprising 7 to 90 per cent C.sub.12 A.sub.7 formed in an underlimed clinker burned to a low free lime, the underlimed condition being at least counterbalanced in the cement by a substance effective to raise the basicity.

Abstract: Silicon carbide articles are formed by wet milling a mixture of silicon carbide having an average particle size less than 10 microns, and colloidal graphite; eliminating powder agglomerates larger than 325 mesh (U.S. Standard Sieve Series); drying the milled powder and pressing it to the desired shape; and finally, firing the preform at approximately 2000.degree. C. in the presence of silicon, converting the graphite to silicon carbide.

Abstract: A full strength, low density concrete is disclosed. The concrete utilizes polyethylene particles for some or all of the aggregate. The particles have a roughened, greatly uneven surface with extreme variations in contour on a macro scale.

Abstract: Water glass composition comprising a water-soluble or water-dispersible silicate binder and an inorganic phosphate curing agent, wherein said inorganic phosphate curing agent is composed of an inorganic solid fine powder comprising as the main ingredient a silicon polyphosphate or its metal salt and said curing agent has an initial dissolution amount (B) of up to 200 mg and an average hydrolysis rate constant (A) of at least 0.2, said initial dissolution amount (B) and average hydrolysis rate constant (A) being defined by the following formula:Y = AX + Bwherein X stands for the lapse of time (minutes) of up to 120 minutes after 1 g of the curing agent has been added to 100 ml of a 4N sodium hydroxide aqueous solution, and Y stands for the integrated amount (mg/100 ml) of phosphoric acid dissolved out of the curing agent into said aqueous solution during the time X.

Abstract: A mixture consisting essentially of fly ash, cement kiln dust and aggregate which through pozzolanic reactions produces a hard, strong, durable mass capable of supporting surfacing.

Abstract: The high temperature dimensional stability and resistance to thermal shock of silica articles is improved by ensuring that from 45-60% by weight of the article consists of crystalline phase silica. Such levels of crystalline phase silica may be attained by intimately mixing finely divided particles of fused silica and crystalline phase silica, molding the mixture to the required shape and then heating the molded mixture at a temperature sufficiently high enough to sinter the particles, but not high enough to cause rapid crystallization of the fused silica.

Abstract: Improved cementitious composition results from a process comprised of mechanical size reduction and activation of a mixture of lime and fly ash and the addition thereto of fly ash and aggregate, as needed, to make a mix of the desired proportions. A quicker and more complete reaction between the lime and fly ash results from deagglomeration of lime particles caused by interaction with the fly ash and/or by the increased availability of reactant materials due to particle size reduction of both the lime and the fly ash. The mechanical size reduction and activation process may be carried out, for example, in a ball mill or centrifugal impact mill.

Abstract: Mono- or di-alkyl phosphate or their alkali metal salts or optionally substituted ammonium salts for use as antifoaming and hydrophobizing additives for hydraulic binders.

Abstract: Electrical insulation grade concrete is prepared by mixing the aggregate and cement with an excess of water and thereafter vacuum deaerating and vacuum dehydrating the resulting mixture.

Abstract: A clay slurry containing 50% or more of non-volatile solids comprising calcined kaolin clay and from 8 - 331/3% of hydrated kaolin clay based on the weight of the calcined clay. Additionally the slurry contains from 0.01% to 10% of a suspending agent such as bentonite clay, hydroxyethyl cellulose, methyl cellulose, carboxymethyl cellulose and a dispersant such as a non-ionic surfactant, an anionic surfactant or an alkanolamine.

Abstract: Improved cementing compositions and their use in cementing operations is disclosed, wherein copolymers of hydrolyzed acrylamide and 2-acrylamido-2-methylpropane sulfonic acid derivatives are used as fluid loss additives for aqueous hydraulic cement slurries.

Abstract: Vinyl ester resin coated glass fibers are disclosed.The coated glass fibers are especially suited for reinforcing cementitious materials.

Abstract: New compositions of matter each consisting essentially of a solid solution of compounds and a halide binder aid. The novel compositions have melting points above 1800.degree. C, high mechanical integrity, low thermal conductivity, and are essentially non-reactive with molten reactive and refractory metals. The novel compositions sinter at 1000.degree. to 1300.degree. C.

Abstract: An early strength hydraulic cement is disclosed in which a clinker rich in C.sub.12 A.sub.7 and poor in CA or C.sub.3 A interground with Portland cement clinker, the resultant early strength cement including at least 10% by weight of C.sub.12 A.sub.7 with a majority of the balance being calcium silicates and including at least 10% by weight of C.sub.3 S.

Abstract: Methods of using aqueous hydraulic cement compositions containing polyamido-sulfonic compounds as flow-property-improving and turbulence-inducing additives are disclosed.

Abstract: A process for retarding the hardening rate of the portland cement and blended hydraulic cement by grinding from about 0.5 to 5.0 weight percent of stannous sulfate based on the dry weight of cement clinker in substitution a portion of gypsum as normally used to eliminate the possibility of false set occuring in ground cement and also improve their qualities.

Abstract: A solid-solid bonded basic refractory having a chemical composition (calculated as the oxides) consisting essentially of MgO in the amount 25% to 97% by weight, CaO 0.9% to 44% by weight, ZrO.sub.2 2% to 57% by weight, and SiO.sub.2 0.5% to 23.5% by weight, the said basic refractory containing a silicate and an alkaline earth metal zirconate, the CaO/SiO.sub.2 ratio being greater than 1.4, there being at least one part by weight of said alkaline earth metal zirconate for each three parts by weight of said silicate, and the CaO to SiO.sub.2 + ZrO.sub.2 ratio being between 0.32 and 1.40, said alkaline earth metal zirconate being capable of co-existing with any basic solid refractory phase at a temperature of at least 1700.degree. C in which solid-solid bonding is maintained between said zirconate and said solid refractory phase in the presence of a liquid phase at a temperature of at least 1700.degree.

Abstract: A method is provided for the production of magnesium oxide -- chromic oxide wherein magnesium chromite of about 3 to 82 weight percent Cr.sub.2 O.sub.3 is mixed with 0.05 to 4 weight percent of CaO or SrO and sintering the mixture at a temperature above about 1750.degree. C.

Abstract: A control method for charging ready-mixed concrete additives batchwise which aims at keeping the slump of ready-mixed concrete within a certain range and making longer transportation by truck mixer possible without degrading the quality, where the slump of ready-mixed concrete is detected electrically as a change in the mixing torque so that, when this detected value reaches a value set beforehand, a motor receives a control instruction to charge additives for adjusting slump into the ready-mixed concrete and so that the operating time of the motor for charging additives and the interval until control operation is reset may be adjusted with a timer.

Abstract: Highly dispersed metal or metalloid oxides are rendered hydrophobic byI. contacting such oxide particles while in the form of an aerogel with a dry inert gas stream in a fluidizing bed at a temperature from 600.degree. to 1000.degree. C and at atmospheric pressure for a period of less than 60 seconds to render the particles absolutely dry and thus activate them;Ii. charging the resultant dried and activated particles in a fluidizing bed with at least one gas-phase organosilicon compound selected from the group consisting of (a) linear organopolysiloxanes (b) cyclic organopolysiloxanes (c) a mixture of both types of siloxanes and (d) a mixture of any of the substances (a)-(c) with an organohalogenosilane at a temperature in the range from 25.degree. to 650.degree. C;Iii. causing said charged particles to react with the organosilicon compounds at a temperature from 35.degree. to 650.degree. C; andIv. finally treating the reaction product with an inert gas stream in a fluidizing bed at temperatures from 500.