RECOMMENDATIONS FOR USE OF FIBRE PRODUCED BY PJSC «STALKANAT-SILUR» FOR PREP-ARATION OF THE STEEL FIBRE CONCRETE MIX
Preparation of steel-fiber concrete mix is carried out, as a rule, in serial forced concrete mixers. It is also allowed to use other types of mixers, providing a homogeneous concrete mix.
Selection of the optimal consistency of the steel-fiber concrete mix for a given workability due to the introduction of plasticizing additives;
uniform supply of fiber to the mixer (feeding a full dose of fiber into the mixer per batch at one time is not recommended);
reduction of the duration (within the technological regulations) of the mixing time of the mixture;
the volume of working batches in the preparation of steel-fiber concrete mixes in forced concrete mixers (in order to exclude the possibility of mixer overload) is recommended to be reduced by 25-30% compared with the volume of similar batches assigned for ordinary (heavy) concrete.
If the fiber content is less than 40 kg in 1 m3 of the mixture, the volume of working batches may not be reduced.
ADDING FIBER TO CONCRETE
Fiber is loaded in a uniform and continuous flow in 3–4 doses at intervals of 1–1.5 minutes (with a rotating drum of the mixer)
The concrete mixer on the automobile chassis is loaded with ready-mixed concrete (or the concrete mix is prepared directly in the mixer) and before unloading, a metered portion of fiber is fed in a uniform stream into the rotating drum with the ready-mixed concrete in compliance with the fiber supply conditions;
the mixing time interval of the steel-fiber concrete mixture should not exceed, as a rule, 3 minutes. The establishment of working intervals of mixing time is carried out empirically during the development of the technological process.
The fiber content in steel fiber concrete (flow rate per 1m3 SPS mixture) is determined by the requirements for its physical and mechanical properties, assigned from the conditions of use. Depending on the scope of steel fiber concrete, the fiber content in it can be recommended as follows, in kg / m3:
- plates of industrial floors – 20 ÷ 40;
- construction of residential buildings – 25 ÷ 50;
- structures and structures that are operated under environmental conditions – 40 ÷ 70;
- construction of tunnels, roads, etc. -50 ÷ 100;
The most common type of fiber:
|Type of fiber||Application|
|Steel wire fiber with curved ends||The most wide-spread type, convenient in processing, not inclined to formation of “hedgehogs” (plain surfaces without projecting parts), holds well in concrete|
ADVANTAGES OF USING FIBRE PRODUCED BY PJSC «PA «STALKANAT-SILUR»
– considerably higher resistance to cracks and bending;
– excellent cohesion with concrete;
– higher impact strength;
– higher water permeability of concrete;
– better behaviour at shrinkage;
– no rejections at reinforcement;
– special equipment is not needed;
– no lumps are formed;
– strengthening of corners and edges;
– simple of usage;
– simple finishing of surfaces;
– extended service life of constructions.
ECONOMIC BENEFITS OF STEEL FIBRE USE
– reduction of coating thickness;
– reduction of labour costs
– reduction of construction period;
– easy manual or machine-made placement.
QUALITATIVE PARAMETERS OF STEEL FIBRE CONCRETE
STRENGTH – maximum stress level that the material can withstand:
~ increase in tensile strength in bending – 50 ÷ 200%;
~ increase in endurance limit – 25 ÷ 30%;
~ increase in compressive strength – 50 ÷ 150%.
DEFORMABILITY – the deformative properties of steel fiber concrete, ceteris paribus, are directly proportional to the degree of volume saturation and inversely proportional to the diameter of the fibers;
~ increase in the value of the initial modulus of elasticity – 10 ÷ 30%;
~ increase in the initial coefficient of transverse deformation – 10 ÷ 20%.
CRACKING RESISTANCE – ability of the material to prevent crack initiation and spreading:
~ increase in crack resistance -30-80%.
FROST RESISTANCE – the frost resistance of steel fiber reinforced concrete increases due to the formation of a finely porous matrix structure with a high content of closed pores and depends on the parameters of the fiber reinforcement and the structure of the concrete matrix:
~ increase in frost resistance of steel fiber reinforced concrete in comparison with ordinary concrete reaches 800%.
CORROSION RESISTANCE – the introduction of fiber reinforcement into concrete significantly improves its structure and ensures high corrosion resistance of the fibers.
WIDE APPLICATION IN THE CONSTRUCTION OF A STEEL FIBER OF PJSC “ON” STALKANAT PRODUCTION “WILL ALLOW YOU TO GET MORE QUALITATIVE AND LONG-TERM DESIGNS!
Wavy Steel Wire Fiber design
a – wave height; b – wave length.
|Symbol||Diameter, mm||Length, mm||Wave length, mm||Wave height, mm|
|URW 60/1,05(10560)||1,05 ± 0,053||60,0 ± 3,0||8,0 ± 1,0||2,0 ± 0,6|
|URW 60/1,0 (1060)||1,0 ± 0,050||60,0 ± 2,5||8,0 ± 1,0||2,0 ± 0,6|
|URW 50/1,0(1050)||1,0 ± 0,050||50,0 ± 2,5||8,0 ± 1,0||2,0 ± 0,6|
Steel fiber is packed in boxes of corrugated cardboard of 10 kg, 20 kg, 24 kg, 25 kg (or other weight at the request of the customer). Boxes are stacked on wooden pallets measuring 1100 x 950 mm in 4-6 rows depending on the weight of the pallet ordered by the consumer. Then the boxes on the pallet are wrapped in stretch film and tied to the pallet with polypropylene tapes. The weight of the pallet can be 900 ÷ 1250 kg.
At the request of the consumer, for greater safety, the fibers in the boxes, pallets packed in stretch film are additionally packed in polypropylene cases.
In addition, steel fiber is packed in special polypropylene bags – “big bags” of 350 kg, 500 kg, 1000 kg. The dimensions of the “big bags” are 1050x900x1000 mm. ” Big bags ” are installed on wooden pallets measuring 1100 x 950 mm and are tied to the pallet with polypropylene tapes. For greater safety during transportation, “big bags” are placed in plywood boxes with dimensions of 1100x950x950 mm, mounted on wooden pallets. Plywood thickness is 18 mm. To facilitate wooden containers, the two opposite walls of the box are made of planks, and the other two walls are made of plywood.
When packing fiber in boxes, oriented laying of fiber is performed, which eliminates the costs of construction organizations due to the formation of lumps of fiber in the process of mixing construction mixtures and concrete.