We perform maintenance to ensure that gravel and crushed stone road surfaces are smooth, as well as have proper water drainage and traffic safety:
- planing — leveling out small potholes and other damage;
- profiling — leveling out transverse corrugations, potholes, and other damage;
- levelling — evening out potholes, transverse corrugations, and other damage, if the layer affected by planing is not sufficient.
The work also includes removing small foreign subjects, and, if possible, setting up local drainage of water from the road surface, and the installation and removal of any necessary equipment to control traffic. We recommend performing planing and profiling tasks when the mineral material is in optimal moisture. Planing and profiling are done in the direction from the edge of the road towards its central axis.
A grader or a tractor with a trailer grader is used for this work.
The renovation and repair of gravel and crushed stone road surfaces are performed in places where maintenance (planing, profiling, or levelling) can no longer achieve the required level of traffic safety and flatness of the road surface.
During the renovation and repair of gravel and crushed stone road surfaces, we carry out the following work:
- renovation of the wear layer of unbound mineral materials;
- removal of potholes and areas of settlement in unbound mineral surfaces;
- addition of coarse gravel in heaving soil areas.
The renovation and repair of gravel and crushed stone road surface includes cleaning the repair site (if necessary), as well as the preparation, delivery, and installation of the necessary materials.
We use mixtures of mineral materials when renovating the wear layer of the road surface. If the renovation of the surface intended with mixing new material into the existing wear layer, fractionated coarse mineral materials or mixtures intended for foundation layers can be used.
Dirt, mud, and water are first removed from the sites where pothole and settlement repairs take place. The mineral material is then poured into the hole, flattened or profiled, and compacted.
Coarse gravel or a mixture of gravel fractions is used for heaving soil areas.
The removal of dust involves binding or coating the particles of gravel or crushed stone road surface or base material with a small amount of binder agent or chemicals, to prevent dust from being lifted up in dry weather.
Regular dust removal on gravel road surfaces is recommended for sections with low but sufficiently constant traffic, and near populated areas. In sections with medium to high traffic, we recommended to coat the surface with a binding agent, such as asphalt, or apply a two-layer surface treatment.
The most commonly used dust removal reagent on national roads is calcium chloride solution or flakes. Dust removal requires the gravel surface to be flat, without potholes and other damage. Planing or profiling of the gravel surface should be done if necessary; it is recommended immediately before (on the same day) the application of the dust removal reagent. The CaCl2 flakes or CaCl2 solution must be applied onto a moist, but not wet surface. The recommended consumption of CaCl2 is 0.20–0.30 kg/m2, few factors should be taken account: road traffic, how many times the treatment takes place, technical condition of the road surface, road location, etc.
Machinery used to perform the work:
- grader — for levelling or profiling the gravel surface before applying the reagent;
- water tank — for moistening the road surface, if necessary;
- spreader — for applying the reagent;
- roller — for compacting the surface.
The repairs of potholes are done to ensure the flatness of the asphalt surfaces, to waterproof them, and to improve traffic safety.
Pothole repair technologies used:
- filling the pothole with hot asphalt using the full technology;
- filling the pothole with hot asphalt using the partial technology;
- filling the pothole with crushed stone and bitumen emulsion using the partial technology;
- filling the pothole with cold bitumen mix using the partial technology;
- laying hot asphalt with paver in individual locations with potholes.
Repairing potholes involves the preparation and delivery of the necessary materials, preparation of the pothole (cleaning, priming, if necessary; also the preparation of its edges by cutting, milling, chipping, or heating) for filling and application of the material.
Machinery used to perform the work:
- a truck with a bitumen emulsion tank and a crushed stone hopper (for pothole repairs with bitumen emulsion and crushed stone);
- a truck with a heating unit (for pothole repairs using hot asphalt);
- a rolleror vibratory plate for compacting the material.
Digging and cleaning ditches is necessary to drain water from the surface and ground water from the road structure.
The type of ditch digging and cleaning work differs depending on what is done with the excavated soil (removal or levelling on-site) and the equipment used (excavator, grader, or manually):
- digging/cleaning the ditch and disposing of the soil off-site;
- digging/cleaning the ditch and levelling the soil on-site;
- cleaning the ditch and restoring its profile with hand work;
- cleaning the ditch and restoring its profile with a grader.
The renovation of ditches by hand work is carried out for small amounts of work (up to 5 m³ in one location), and in places where it is not possible to use machinery (there are underground cable lines, overhead lines, poles, and other utilities, trees).
An excavator or a front loader/excavator equipped with a planing bucket or a profile bucket are the most widely used for digging and cleaning ditches.
The installation or replacement of road signs and road sign poles involves determining the location of the sign, setting up a foundation for its base, installing the base, and attaching the road sign.
The material, size, and location of road signs must meet the requirements of LVS 77-1,2,3, LVS 85, and EN 12899-1.
Metal pipes or wooden poles are used as bases for installing road signs. The length of the pole is determined based on the width of the road, the dimensions of the road signs, and the elevation of their lower edge above the road surface.
The installation and replacement of road signal posts includes the preparation of the worksite, and if necessary, the removal of existing road signal posts, marking the locations for the signal posts, preparation of the base for the signal posts, installation of the signal posts, ensuring compliance with the geometry, as well as the clean-up of the worksite.
Depending on the situation, signal posts are installed on the roadside (type D3) or above the barrier (type D4).
The installation, replacement or renovation of a safety barrier includes the preparation of the worksite, and if necessary, the removal of existing barriers and fastening elements, determining the location of the barriers and their elements, installing frames, primary and additional elements (initial sections, final sections, shock absorbers), correcting the geometry of the barriers in all dimensions, final attachment, installation of additional equipment (reflectors, vertical markings, signal posts).
The replacement of a culvert (including the extension or replacement of damaged culvert sections) involves all the work, materials, and equipment necessary to restore, replace, install a culvert (or its sections), including the removal of the road surface and its structural layers, as well as the later construction of the road surface and its structural layers of the road surface not related to binders, but not including the restoration or construction of the layers of the road surface that contain binding agents.
If during its operationuse, a culvert or its sections is settled or were damaged, then the cause of this must be determined and corrected solved as part of replacing the sections.
The work must be performed in the following order:
- removal of the road surface structure;
- excavation of the ground, down to the foundation of the culvert;
- removal of damaged culvert sections;
- visual inspection of the foundation (determining whether the concrete foundation has any cracks, whether the actual thickness of the crushed stone and gravel base matches the design thickness);
- if necessary, water must be pumped out of the construction pit (in wet soils);
- renovation of the culvert base, if necessary;
- installation of the culvert or culvert section;
- the filling of the culvert or culvert sections with soil must be done simultaneously from both sides;
- the road surface structure must be restored;
- clean-up of the construction waste.