Abstract: Microparticles having crystalline needle or rod-shaped structures of, for example, an ettringite mineral grown and attached radially from their surface. A method including nucleating and growing crystalline needles/rods from the surface of a particle in the presence of a solution of calcium, sulfur, and aluminum such as calcium sulfoaluminate, lime and calcium sulfate is described. One example is the radial growth of ettringite needles on the surface of fly ash particles in calcium sulfoaluminate-based cement paste and concrete.

Abstract: Synthetic fibers, such as polypropylene fibers, are mixed in a shrinkage compensating concrete to provide restraint in lieu of conventional steel reinforcement used in a shrinkage compensating concrete. While the synthetic fibers have a low elastic modulus and low strength, they act to restrain expansion of the concrete in the same way that conventional steel rebar does. In addition, only a small amount of the synthetic fibers are needed to restrain the expansion. As a result, shrinkage compensating concrete can be used in more varied applications, and can be provided more quickly, easily and inexpensively. Construction time requirements and expenses of concrete structures are correspondingly reduced.

Abstract: Synthetic fibers, such as polypropylene fibers, are mixed in a shrinkage compensating concrete to provide restraint in lieu of conventional steel reinforcement used in a shrinkage compensating concrete. While the synthetic fibers have a low elastic modulus and low strength, they act to restrain expansion of the concrete in the same way that conventional steel rebar does. In addition, only a small amount of the synthetic fibers are needed to restrain the expansion. As a result, shrinkage compensating concrete can be used in more varied applications, and can be provided more quickly, easily and inexpensively. Construction time requirements and expenses of concrete structures are correspondingly reduced.

Abstract: A calcium sulfoaluminate-based concrete with a permeability of less than 1000 Coulombs. Rapid-setting low chloride-ion permeability calcium sulfoaluminate (CSA) cements and concretes include CSA and a suitable polymer such as a sol-gel derived, organic-inorganic, silica based hybrid coating solutions of polystyrene-butylacrylate polymers containing active silanol groups protected by hydroxyl groups containing polyalcohol, or other polymers. Such polymers may be added as powders or as liquid in the finish mill. Other rapid-setting low chloride-ion permeability (CSA) cements and concretes include CSA with selected particle size distributions, and do not require use of any polymer. These CSA cements and concretes have low chloride-ion permeability, high early strength, fast setting times, low-shrinkage, and high freeze-thaw resistance.

Abstract: Synthetic fibers, such as polypropylene fibers, are mixed in a shrinkage compensating concrete to provide restraint in lieu of conventional steel reinforcement used in a shrinkage compensating concrete. While the synthetic fibers have a low elastic modulus and low strength, they act to restrain expansion of the concrete in the same way that conventional steel rebar does. In addition, only a small amount of the synthetic fibers are needed to restrain the expansion. As a result, shrinkage compensating concrete can be used in more varied applications, and can be provided more quickly, easily and inexpensively. Construction time requirements and expenses of concrete structures are correspondingly reduced.

Abstract: Synthetic fibers, such as polypropylene fibers, are mixed in a shrinkage compensating concrete to provide restraint in lieu of conventional steel reinforcement used in a shrinkage compensating concrete. While the synthetic fibers have a low elastic modulus and low strength, they act to restrain expansion of the concrete in the same way that conventional steel rebar does. In addition, only a small amount of the synthetic fibers are needed to restrain the expansion. As a result, shrinkage compensating concrete can be used in more varied applications, and can be provided more quickly, easily and inexpensively. Construction time requirements and expenses of concrete structures are correspondingly reduced.

Abstract: A shrinkage compensating cement exceeding the ASTM standard specification limiting 28 day expansion to 115% of the 7 day expansion. 28 day expansions of 120-200% are contemplated. The expansion takes place over an extended period of time, to better offset the shrinkage occurring as the concrete dries. The development of tensile stresses in the concrete is reduced and also is delayed, allowing more time for the tensile strength of the concrete to increase as the concrete dries. Shrinkage cracking is consequently significantly reduced.

Abstract: An apparatus and method for testing brittle materials in tension includes a gripping sleeve of a viscous yieldable material placed over a specimen and a pulling sleeve adapted for placement over the gripping sleeve and for attachment to a testing apparatus. The pulling sleeve imparts load to the gripping sleeve which in turn imparts load to the specimen. Elements are provided to minimize elastic rebound.

Abstract: An improved expansive cement and method of forming same. An expansive clinker containing a stable calcium alumino sulfate compound is separately ground to a selected surface area greater than about 4600 sq. cm/gm. The ground expansive clinker is then blended with a ground cement clinker and with gypsum to form the expansive cement. The expansive cement formed in accordance with the present invention requires less of the expansive clinker than expansive cements known in the art to achieve the same magnitude of expansion.

Abstract: A multiple level building structure utilizing a first set of precast reinforced concrete modules having integral supporting legs separated by a second set of precast or in situ cast reinforced concrete modules, each of the second set of modules being supported along opposite side margins by members of the first set of modules; the structure also including, if desired, a third set of modules of greater width than the first or second set of modules, the modules having tendon guideways therein and being secured together by removable post tensioning tendons strung through the guideways.

Abstract: A multiple level building structure utilizing a first set of precast reinforced concrete modules having integral supporting legs separated by a second set of precast or in situ cast reinforced concrete modules, each of the second set of modules being supported along opposite side margins by members of the first set of modules; the structure also including, if desired, a third set of modules of greater width than the first or second set of modules, the modules having tendon guideways therein and being secured together by removable post tensioning tendons strung through the guideways.

Abstract: A multiple level building structure utilizing a first set of precast reinforced concrete modules having integral supporting legs separated by a second set of precast or in situ cast reinforced concrete modules, each of the second set of modules being supported along opposite side margins by members of the first set of modules; the structure also including, if desired, a third set of modules of greater width than the first or second set of modules, the modules having tendon guideways therein and being secured together by removable post tensioning tendons strung through the guideways.

Abstract: A method of assembling building structures utilizing precast concrete building units which are positioned side-by-side and end-to-end as well as stacked to form a multistory structure; the units being secured together by tendons freely threaded through horizontal and vertical chases provided in the building units, placed under tension and anchored at their extremities.

Abstract: A building construction utilizing precast concrete building units which are positioned side-by-side and end-to-end as well as stacked to form a multistory structure; the units being secured together by tendons freely threaded through horizontal and vertical chases provided in the building units, placed under tension and anchored at their extremities. The building units may also include precast beams containing longitudinal catenary tendons anchored at the end extremities of each building unit, the units being bolted in end-to-end relation.