A method of preparing high strength coral concrete, wherein the high strength coral concrete is prepared from raw materials of the following parts by mass: 25˜63 parts of cementing materials, 45˜58 parts of coral aggregate, 10˜16 parts of mixing water and water reducer 2˜5% the weight of the cementing materials; the weighed coral aggregate, mixing water, water reducer and 55˜85% of the cementing materials are stirred in an agitator for 10˜15 minutes; the rest of cementing materials are added in batches before initial setting and stirred; then poured and removed from the mould after 24 hours, cured in mixing water at normal temperature for 28 days, to get the high strength coral concrete.

The present invention comprises a product. The product comprises a first mineral in particulate form and having a first pozzolanic reactivity and a second mineral in particulate form and having a second pozzolanic reactivity greater than the first reactivity, wherein the surface of at least some of the particles of the first mineral is at least partially covered with particles of the second mineral. A method of making the composition of the present invention is also disclosed.

The present disclosure relates to a “concrete slotted floor” manufactured from an UHPC composition which exhibits superior crack resistance due to uniform distribution of reinforcing fibers even when a residing surface is located below, allows early demolding due to fast initial setting time and exhibits improved cleaning efficiency due to maximized surface water repellency, an “UHPC composition for manufacturing the same” and a “method for manufacturing a concrete slotted floor using the same”.

The present invention provides a concrete vacuum tube segment for a hyper-speed transportation system using ultra-high performance concrete (UHPC) and a manufacturing method thereof. A concrete vacuum tube segment for a hyper-speed transportation system can be easily manufactured using UHPC, in which shrinkage and structural cracking do not occur due to mixing a binder and a short fiber to secure airtightness on the basis of a maximum fill theory, and accordingly, shrinkage of the concrete vacuum tube segment can be reduced even in a partial-vacuum state in which the magnitude of drying shrinkage is very small and quick drying occurs; when mixing the UHPC, an antifoaming agent is mixed and a circular vacuum pump is used to remove generated entrapped air to minimize the entrapped air; and a capsule-type crack healing material, which is able to repair fine cracks, is compacted to secure airtightness of the concrete vacuum tube segment.

An admixture for making a high-strength concrete with any type of water, including potable water, freshwater, saltwater, brackish water, reclaimed water or any other non-potable water. The admixture consists of basalt fibers, graphene nanoplatelets, calcium sulfide, calcium chloride, magnesium oxide and nanoclays. The admixture can be added to the cement to supplement it to increase the overall compressive strength, or the amount of cement used can be reduced by the amount of admixture added to shorten cure times. A concrete mix can also be prepared by replacing the calcium chloride with silica fume, reducing the amount of cement used, and introducing locally sourced aggregates, coarse and fine, to yield Ultra High Performance Concrete. Products made from the concrete incorporating the admixture have increased compression strength, improved cure times, reduced water consumption and corrosion, increased durability and workability, drastically reduced freeze-thaw effects, and superior crack control.

The present invention belongs to the field of composite materials, and particularly to a non-flowable quick-setting phosphate cement repair material with strong cohesive forces and the preparation method thereof. The material comprises the following raw materials in percentage by weight: 20% to 40% of sand, 5% to 12% of ammonium dihydrogen phosphate, 10% to 25% of magnesium oxide, 2% to 8% of fly ash, 30% to 60% of rubber powder, 6% to 10% of silica fume, 0.35% to 0.6% of a polycarboxylate high efficiency water-reducing agent, 1% to 5% of sodium silicate, 1.5% to 2% of a polypropylene fiber, 0.5% to 2% of a retarder, and 8% to 10% of water. The material is used as the repair material for the special positions of bottom boards of bridges or facades of buildings which are damaged, and the repair effect thereof is remarkable.

According to aspects of the present disclosure, a composition is disclosed, which can be utilized to construct a retention structure, e.g., for use with hardscape such as pavers, tile, stone, and other building materials. The composition is a mixture of a cement component (e.g., Portland cement), a sand component, a gravel component, a silica fume component, and fiber component, the above-components mixed in varying ratios. When the cement component, sand component, gravel component, silica fume component, and fiber component are mixed in an effective amount, combined with a water component, and applied against a hardscape, the composition, once cured, defines a retention structure that abuts to, but is not adhered to the hardscape.

The use of an additive, including at least one water-soluble polymer, which is a homo-or copolymer of at least one monoethylenically unsaturated carboxylic acid, and optionally at least one alkali silicate as a liquefier for geopolymers. The additive can be produced in a simple and inexpensive manner and is particularly suitable for liquefying geopolymers, in particular geopolymers containing metakaolin.

Mineral fines reduce OPC content in concrete, mortar and other cementitious compositions, typically in combination with a pozzolanically active SCM. Mineral fines can replace and/or augment a portion of hydraulic cement and/or fine aggregate. Mineral fines can replace a portion of cement binder and fine aggregate as an intermediate that fills a size void between largest cement particles and smallest fine aggregate particles. Supplemental lime can enhance balance of calcium ions in the mix water and/or pore solution. Supplemental sulfate can address sulfate deficiencies caused by high clinker reduction, use of water reducers and/or superplasticizers, and SCMs containing aluminates. Concentrated or pure carbon dioxide (CO.sub.2) can be used to passivate alkaline values in highly alkaline materials, such as concrete washout fines, CKD, class C flyash, incinerator ash, bottom ash, or biomass ash. CO.sub.2 passivation or sequestration can be carried out before, during or after forming an initial concrete mix.

The present invention comprises a product. The product comprises a first mineral in particulate form and having a first pozzolanic reactivity and a second mineral in particulate form and having a second pozzolanic reactivity greater than the first reactivity, wherein the surface of at least some of the particles of the first mineral is at least partially covered with particles of the second mineral. A method of making the composition of the present invention is also disclosed.