technologies
These properties make it suitable for use in the construction of structures where the advantages of UHPC Valucem C120 can be better utilized than in structures made of conventional concrete.
Bridges of small to medium span, bridge segments, prestressed bridge girders, reinforcement of horizontal and vertical load-bearing frames, facade features, facing slabs, monolithic thin-wall constructions, street furniture (such as benches and rubbish bins), architectural and design work (statues, sculptures).
High material properties; grade C120 based on cylindrical compressive strength, in accordance with TP 267 MD ŘSD
An almost unlimited service life due to the high density of UHPC Valucem C120 and its resistance to common environmental factors
The ability to design three-dimensional thin-walled elements with sufficient load-bearing capacity, achieved in many cases without the need for soft reinforcement
Its fine grain and very high fluidity make it possible to create perfect impressions of molds, reliefs, and three-dimensional patterns
The low weight and subtlety of of Valucem elements reduces the requirements for transport and production technology
With the right additives, UHPC Valucem C120 can be used in 3D printing
UHPC Valucem C120 saves up to 40% in material and reinforcement volume and reduces transportation costs. In bridge construction, it can even replace horizontal waterproofing.
Multicomponent fine-grain cement-based composite produced from prime fractions of silica filling of maximum grain size of 2mm, latent-hydraulic fillers and modifying additives. The mixture contains a liquid superplasticizer and a selected type and dose of fibres (steel, polymer). The mixture contains a liquid superplasticizer and a selected type and dose of fibres (steel, polymer). The composition ensures high compressive and tensile strength in bending, high adhesion to the substrate and easy filling of even very complex mould shapes. The colouring can be altered with pigments.
UHPC Valucem C120 can be used to manufacture thin (shell) precast structures, as well as precision and complex-shaped components, such as facade elements, street furniture, and replacements and replicas of stucco and stonework products.
| Characteristics at 28 days a) | Symbol | Unit | Norm | UHPC Valucem C120 |
|---|---|---|---|---|
| Strength grade | fck | MPa | EB 1992 - 1 - 1 | C 120 |
| Recommended dosage of steel microfibres Bulk weight | Vf | Bulk percentage | TP 267 MD ČR | 1,5 |
| Bulk weight | ρ | kg/m³ | EN 12390 - 7 | 2400 ± 2 % |
| Characteristic cylindrical strength | MPa | EB 1992 - 1 - 1 | 120 | |
| Average cylindrical compressive strength on a 100/200 mm cylinder | fcm | MPa | EN 12390 - 3 | >130 |
| Characteristic residual flexural tensile strength b) | fctk,f | MPaMPa | TP 267 MD ČR | >12 |
| Average residual flexural tensile strength b) | fR1m | MPa | EN 14651 | >17 |
| Residual strength class from crack opening displacement at 3,5 mm/0,5mm ratio b) | fR3m/fR1m | MPa | EN 14651, TP 267 MD ČR | >0,7 |
| Resistance to deicing agents | Maximum waste cycles2 | Czech technical standard 731326, method C | >200 | |
| Elastic modulus | E | GPa | ISO 1920 - 10 | >46 |
Note
a) These properties characterize the Valucem C120 UHPC base series. Depending on the project’s objectives and the requirements for structural elements, these properties can be adjusted in collaboration with the UHPC supplier.
b) The parameter significantly depends on the type and dosage of steel microfibres and can be altered according to the needs of the design and requirements of the construction elements
The use of high-value concrete in the reinforcement of horizontal bridge structures
The project for the verification of UHPC laying was aimed at improving the physical and technical parameters of existing horizontal elements of bridge structures (bridge decks, crossbeams, etc.) and slab structures placed on the ground (roadways, parking lots, floors, etc.).
By installing a structural layer made of UHPC, it is possible—particularly in older bridges—to increase the live load capacity and create an alternative, durable horizontal layer with insulating properties. However, this application is also possible in newly constructed bridge structures.
There is often no choice but to remove the existing structure and replace it with a new, more load-bearing one.
A newly applied layer of high-performance concrete is capable of integrating several functions. This capability is the source of this technology’s high added value. It combines the function of structural reinforcement with that of a waterproofing layer, and is also capable of creating a highly resistant and durable final surface suitable for foot traffic or vehicle traffic. Given its unique mechanical and physical properties, the UHPC Valucem C120 material can be applied in thinner structural layers. In addition to placing less load on the structure, this means a smaller volume of material used—and thus lower consumption of primary raw materials—as well as lower transportation costs and costs for heavy machinery. Ultimately, all of this results in a reduced environmental impact.
During the development of this technology for reinforcing horizontal surfaces or surfaces with a slight slope, a modification of the fresh UHPC Valucem C120 mix was developed to allow for placement even on surfaces with a slight slope. At the same time, procedures for finishing the final surfaces were verified to ensure that the final surface possesses sufficient slip-resistant properties.
Technical and application conditions
The use of UHPC in the reinforcement of horizontal surfaces of bridge structures requires that the newly formed UHPC reinforcement layer is applied to the existing exposed concrete /binding / layer for good anchorage of the reprofiling layers. The exposed subgrade has to be sufficiently load-bearing and “open”. After cleaning, there are visible fine and coarse aggregate grains on the surface, including larger air pores in the mortar portion.
A key characteristic of fresh UHPC mix is its high flowability; the mix is essentially self-leveling. By adding suitable admixtures to the fresh mix, it is necessary to increase the mix’s cohesion so that the UHPC layer can be sloped. UHPC modified with Valucem C120 allows for the creation of sloped layers with a slope of up to 6%.
Within practical tests and implementations dealing with reinforcement and final surface treatment, the following has been successfully carried out:
- reinforcement of a brick columns in the premises of PREMIX servis, Libiš
- repair of footbridge in- Chemopetrol industrial estate
- repair of a parking area – company PREMIX servis, Libiš
- repair of an influx tank in Chemopetrol industrial estate
- reinforcement of the crown of an aeration tank of a sewage water disposal plant in Chemopetrol industrial estate
