A method for reinforcing a structure comprising the following steps: preparation of UHPFRC comprising a cement precursor mix, of water, a fluidizing agent and metal fibers, transporting the UHPFRC by pumping to a suitable spray nozzle, spraying the mix onto a surface of the structure by the addition of a compressed air stream in the spray nozzle.

The invention relates to processes for making improved ultra-high performance concrete with plasma-treated inclusions and articles made from the same. The invention includes a process for producing silicon carbide and multiwalled carbon nanotubes by heating agricultural waste husks in an inert atmosphere to a temperature higher than 1300 degrees C. to obtain a mixture containing silicon carbide and MWCNTs, and treating the mixture to extract the silicon carbide and MWCNTs for use as microinclusions in ultra high performance concrete.

An anti-blast concrete and a method of fabricating an anti-blast structure member using such anti-blast concrete are disclosed. The composition of the anti-blast concrete according to the invention includes, in parts by weight, 1.0 part by weight of cement, 1.0 to 2.5 parts by weight of fine aggregates, 1.0 to 2.5 parts by weight of coarse aggregates, and a plurality of reinforcing fibers. The weight ratio of the reinforcing fibers to the cement ranges from 0.5% to 3%. The plurality of reinforcing fibers are a plurality of carbon fibers or a plurality of aramid fibers. A test body, made of the anti-blast concrete of the invention, has an average number of times of repeated impacts at an impact energy of 49.0 Joules equal to or larger than 41 times at 28 days of age.

A precast concrete structure formed of a cementitious mixture is provided, the cementitious mixture comprising a mixture of: (a) cement, (b) silica fume, (c) supplemental material (limestone and/or slag), (d) masonry sand, (e) water and ice (f) plasticizers and (g) workability admixtures. The result is an improved concrete for use in the formation of long span bridge elements that are simple and safe to manufacture and having improved properties. The instant abstract is neither intended to define the invention disclosed in this specification nor intended to limit the scope of the invention in any way.

A precast concrete beam is provided in construction of a long span bridge structure. The beam is formed of a plurality of aligned modular elements each formed of prestressed UHPC mix as a unitary body. The UHPC mix includes discontinuous fibers distributed randomly throughout a concrete matrix. Each modular element is aligned modular and connected by an epoxy grout to adhering adjacent element joints. Finally, post-tensioning of the entire beam reinforces and affixes the plurality of aligned modular elements into a single long span beam.

A precast concrete beam A beam for use in construction of a long span bridge structure comprising: a reinforcing member having a geometric configuration selected from a group consisting of: a “U” tub beam with composite deck system; a decked I-beam; and an adjacent box beam; said geometric configuration formed of a UHPC mix having: an initial compressive strength, f′.sub.ci=10.0 ksi; a compressive strength at service, f′.sub.c=17.4 ksi; a modulus of elasticity of concrete, E.sub.c=6500 ksi; a residual rupture stress, f.sub.rr=0.75 ksi; and a concrete unit weight, w.sub.c=0.155 kcf; and
said UHPC mix further comprises a plurality of discontinuous fibers distributed randomly throughout a concrete matrix, said plurality of discontinuous fibers formed of a material selected from the group consisting of: steel; polypropylene; nylon; polyvinyl alcohol; polyolefin; polyethylene; polyester; acrylic; aramid; carbon; silica glass; basalt glass; glass fiber-reinforced polymer; and basalt fiber-reinforced polymer.

Cementitious compositions include: a) 4-80 wt.-%, preferably 26-75 wt.-%, especially 30-66 wt.-% of a cementitious binder, especially of Ordinary Portland Cement, b) 5-95 wt.-%, preferably 20-73 wt.-% more preferably 33-66 wt.-%, of aluminum oxide, and c) 1-15 wt.-% preferably 2-10 wt.-%, more preferably 3-6 wt.-% of fibers. Such cementitious compositions have a very high strength and are used for example for concrete repair or as grouting materials.

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 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 disclosure relates to ultra-high density concrete composite containing super-absorbent polymer (SAP)-Attached Fibers, suitable for making a near-vacuum tube for hyperloop transportation system, a method for manufacturing the ultra-high density concrete composite, a method for manufacturing a concrete member using the ultra-high density concrete composite and an ultra-high density concrete member manufactured by the method.