The invention relates to ultra-high-performance steel fiber reinforced concrete, which is prepared from cement, silica fume, standard sand or river sand, a water reducing agent, water and copper-coated steel fibers. A preparation method of the ultra-high-performance steel fiber reinforced concrete comprises the steps of adding the cement, the standard sand or river sand, the silica fume and a component B of the water reducing agent into a forced mixer, and evenly mixing to prepare a dry material; adding half of a component A of the water reducing agent and the water into the dry material, and evenly mixing; adding the rest half of the component A of the water reducing agent and the water into the dry material, and evenly stirring; adding the steel fibers for 3-5 times, and continuously stirring until the steel fibers are evenly distributed. Tests prove that test pieces prepared from the ultra-high-performance steel fiber reinforced concrete have the compressive strength exceeding 150MPa and the ultimate tensile strength exceeding 6MPa, have good flowability and are easy to maintain. The ultra-high-performance steel fiber reinforced concrete is suitable for lower structures of reinforced concrete bridges, steel-concrete composite structure bridges and the like as well as lower structures of piers and abutments of the bridges.

Ultra-high-performance steel fiber reinforced concrete and preparation method thereof

The invention belongs to the technical field of concrete additives and relates to a high freezing resistance water permeable concrete additive and a preparation method thereof The high freezing resistance water permeable concrete additive consists of the following components in parts by weight: 5-10 parts of mixing materials, 05-10 parts of a water reduction agent, 01-1 part of a thickening agent and 3-6 parts of a water repellent agent, wherein the mixing material is silicon ash or coal ash; and the granularity of the mixing material is 300-400 meshes The preparation method comprises thefollowing steps: mixing the mixing material, the water reduction agent, the thickening agent and the water repellent agent according to the parts by weight, grinding, stirring the mixed material at amedium speed till the components are uniform, and discharging The additive provided by the invention is capable of enriching fine capillary cavities and micro cracks in a cementing layer of water permeable concrete, improving the strength of a cement adhesive layer, and improving the strength of the water permeable concrete, so that the freezing resistance of the concrete is improved In addition, due to adoption of the water repellant agent, a water repellant surface is formed on the surface of the cementing layer of concrete, so that water inside the concrete can be well discharged, and thefreezing resistance and the water permeability of the concrete are improved

High freezing resistance water permeable concrete additive and preparation method thereof

The invention discloses a previous concrete improving agent. The previous concrete improving agent comprises the following raw materials in parts by weight: 80-90 parts of cement, 6-10 parts of mineral powder, 6-10 parts of silica fume and 1-3 parts of an additive, wherein the additive is a mixture of polyacrylamide, a polycarboxylate superplasticizer, a retarder, a thickening agent and redispersible gelatine powder. Meanwhile, the invention provides a preparation method of the previous concrete improving agent. The preparation method comprises the following steps: weighing the cement, the mineral powder, the silica fume and the additive in parts by weight; and mixing and uniformly stirring to obtain the improving agent. The previous concrete improving agent has the beneficial effects thatthe integral strength of previous concrete is improved, durability of the previous concrete is enhanced, and workability of the previous concrete is improved.

Previous concrete improving agent and preparation method thereof

The invention discloses a preparation method for factory-produced pervious concrete. An aggregate is poured into a concrete blender, 50% water is added for stirring for the first time, the aggregate is wetted by stirring for 30 s, then a cement material is poured into and stirred for 30 s, the remaining 50% of water is added for stirring, a reinforcing agent is poured into after stirring in the concrete blender is conducted for 30 s, and finally stirring in the concrete blender is conducted for 60 s to complete the preparation; the cementing material is P.O 42.5 ordinary Portland cement and P.O 42.5 ordinary Portland cement with 10% silica fume. According to the preparation method, by adding water for stirring twice and adding the cementing material, a mixture produces 'ball effect' duringthe stirring process, the rheological property of the concrete is improved, and the strength of the concrete can still be improved; the prepared reinforcing agent is added into the concrete, so thatthe concrete can be transported by a concrete mixer truck, the work performance is prolonged, and the strength of later use is still not lost.

Preparation method for factory-produced pervious concrete

The invention discloses a preparation method of a concrete compound air entraining agent, and belongs to the technical field of preparation of concrete admixtures. The preparation method comprises the steps that isotridecyl alcohol is taken as a raw material, sodium methylate is taken as a catalyst, the isotridecyl alcohol and the sodium methylate are subjected to vacuum dehydration, and then the dehydrated isotridecyl alcohol, the dehydrated sodium methylate and ethylene oxide are subjected to ring opening polymerization to synthesize isotridecyl alcohol polyoxyethylene ether; then sulfamic acid and carbamide are used for sulfonating and modifying the isotridecyl alcohol polyoxyethylene ether to obtain a sulfonated and modified isotridecyl alcohol polyoxyethylene ether solution with both advantages of negative ions and advantages of a non-ionic type air entraining agent; and finally, the sulfonated and modified isotridecyl alcohol polyoxyethylene ether solution is compounded with alpha-olefin sulfonate and silicone polyether emulsion to obtain the high-performance concrete compound air entraining agent. The air entraining agent prepared through the preparation method has a good air entraining effect, the average pore size of introduced bubbles is small, the stability of the bubbles is high, the strength of concrete is slightly reduced, the durability of the concrete is remarkably improved, the workability of the concrete is obviously improved at the same time, the slump loss of the concrete is reduced, the strength of the concrete is not reduced, and the preparation method has good application prospects.

Preparation method of concrete compound air entraining agent

The invention discloses a specialadmixture for pervious concrete and application of the specialadmixture. Thespecial admixture comprises the following materials in weight percent: 5 to 15 percent (solid content) of a water reducing agent; 0.1 to 1 percent of a retarder; 0.1 to 1 percent of a thickener; 15 to 25 percent of an early strength agent; 25 to 50 percent of a water-repellent agent; 25 to 50 percent of rubber powder. The admixture overcomes the problem that the existing pervious concrete is not easy to transport bya tanker, and ensures that the phenomenon of blocking cannot occur when the pervious concrete is put into a tanker after the admixture is used, has excellent service behavior after the pervious concrete is discharged from the tanker, and has excellent cohesiveness, without phenomena of bottom sealing and hole blocking.

Specialadmixture for pervious concrete and application ofspecialadmixture

The invention discloses steel fiber concrete with high fracture resistance and a preparation method thereof. The steel fiber concrete comprises matrix concrete and steel fiber, and is characterized in that: the volume percent content of the steel fiber is 3.5%; and the used raw materials comprise the following materials by weight: 125-175Kg of water, 500-542Kg of cement, 25-38Kg of silica fume, 40-60Kg of fly ash, 500-662Kg of sand, 800-953Kg of stone, 10-16Kg of a pumping agent, and 250-273Kg of steel fiber. During stirring of concrete production, the steel fiber in the steel fiber concrete disclosed by the invention cannot agglomerate easily, so that the steel fiber concrete has good construction workability and can meet pouring construction requirements; the breaking strength of the concrete is greatly improved, high-performance concrete with the breaking strength of 20MPa is successfully prepared, and under an equal strength condition, the thickness of a concrete pavement is reduced, and the construction cost is reduced. This special type of concrete can be applied to construction parts with high requirements on crack control, toughening and shock resistance, and can be widely applied to road, bridge and pavement constructions.

Steel fiber concrete with high fracture resistance and preparation method thereof

The invention discloses a special admixture for full-lightweight ceramsite concrete and a preparation method. The special admixture is characterized by being prepared from the following composition materials in percentage by weight: (A) an air-entraining ingredient, (B) thickening and water retention ingredients, (C) a bubble stabilizing ingredient and (D) deionized water. The admixture is independent of water reducing type admixtures (pumping aids) on the market and is used in a manner of being combined with the water reducing type admixtures. Through adding small and stable bubbles, the size distribution of mortar is optimized, and the placeability of the full-lightweight ceramsite concrete can be greatly improved through the microbead effect of spherical and uniform small bubbles. By adding the admixture, the volume weight of the mortar in the full-lightweight ceramsite concrete is lowered, so that the difference between the volume weight of ceramsite and the volume weight of the mortar is reduced, and the rate of floating of the ceramsite is lowered; and the thickening and bubble stabilizing ingredients are further added into the admixture, on one hand, the viscosity of a system is improved by the thickening ingredient so as to inhibit the floating of the ceramsite, on the other hand, by adding the thickening ingredient, the bubbles can more stably exist in the ceramsite concrete.

Special admixture for full-lightweight ceramsite concrete and preparation method

The utility model discloses a high toughness steel fibre concrete road surface structure, its characterized in that: shed including wearing layer, steel fiber concrete base member, steel fibre that a layer A, steel fibre shed a layer B, a layer C, steel construction bottom surface are shed to the steel fibre, realizing making steel fibre evenly distributed inside the base member concrete under the high volume of the mixing condition, avoided fibre conglomeration inside the concrete, and then realized the high transverse strength performance of base member concrete. The design of unique overall structure has further improved the transverse strength of concrete road surface: inside pavement concrete was goed deep into to the anchor structure, steel construction bridge floor and concrete combined more closely, premium propertiess such as this kind of road surface has better toughness, anti -seismic performance, antily splits, shocks resistance, wear -resisting. Because anti book, compressive strength far surpass in ordinary steel fiber concrete, under the equal strength requirement, it is lighter to conduct oneself with dignity, can reduce bridge floor engineering self load, has also practiced thrift engineering cost.

High toughness steel fibre concrete road surface structure

The utility model discloses a device for testing self -compaction microdilatancy steel pipe concrete expansion rate, its characterized in that: including concrete placement examination mould, fixed examination mold base, 4 vertical displacement detection device and scalable connecting rod, 4 hoop displacement detection device, 4 scalable connecting rod fixed baseplate, 1 annular base, closed piece, the last steel bones RACK of annular base, spirit level, closed piece hasp, the utility model discloses the equipment is convenient, and scalable connecting rod, displacement testing arrangement and scalable connecting rod fixed baseplate adopt the screw fixation, easy adjustment, and convenient and fast connects. Concrete test adopts the rigidity examination mould that 1mm is thick, and elasticity is good, recovers after the deformation, and in the recess of examination mould side was placed in to closed piece, the recess upper end had closed hasp, and the sealability is strong, guarantee the concrete slurry not beyond the scope of the hourglass, the steel -pipe column surface after the shaping is smooth.

Liu Dengxian

Papers

Specialadmixture for pervious concrete and application ofspecialadmixture

Steel fiber concrete with high fracture resistance and preparation method thereof

Special admixture for full-lightweight ceramsite concrete and preparation method

High toughness steel fibre concrete road surface structure

A device for testing self -compaction microdilatancy steel pipe concrete expansion rate