Low Construction Directorate executes road and bridge construction. It is specialized in the vertical planning, concrete and decorative coverings, concrete “UNI” pavement, parking area concrete elements, sidewalk and concrete plates, sidewalk borders, concrete strips of asphalt pavements, supporting walls, road pavements, reverse embankments, external sewage.
The Directorate’s work is exceptionally professional, qualitative and within short terms. It has at its disposal equipment and highly skilled staff, including technical staff with extensive professional experiences in the construction and field supervision of a major part of the road artery of the Republican road network under the PHARE Program and Hemus Motorway.

1. Making of road asphalt covering

Tempo Stroy Engineering Ltd. performs all major processes for preparation, packing and measuring of the density of the earth bed, the construction of all transverse and longitudinal drainages and trenches.
The making of road asphalt covering requires several stages:
A sub foundation layer is made by using sand, coarse aggregate, crushed stone and other materials. The packing is done by vibration and static rollers at optimal water contents.
Then the laying of a crushed stone layer, slag or coarse aggregate follows. The crushed stone meets the quality and the requirements of Bulgarian State Standard 2282.
Next step is the profiling of the covering by a grader and its packing by vibration rollers- 6–7 or 10–14 t. In order to achieve an optimal result 2 passes without vibration and 5–6 passes with vibration are necessary and sprinkling with water, after which there are other two passes – static for smoothing.
Types of asphalt coverings and layers:
• Bituminous crashed stone – with different thickness depending on the loading.
• Not packed asphalt concrete – with thickness of 4–6 cm.
• Wearing packed asphalt concrete – with thickness of 4 cm.
Under the asphalt concrete covering 1st bituminous spilling is laid and between the separate asphalt layers a second bituminous spilling is made for bonding.
The asphalt mortars are laid by asphalt laying machines. They are packed by static, vibration or pneumatic rollers.
In order to achieve good thickness 10–20 passes per point are necessary.
The thickness of the asphalt plates is checked using asphalt cuttings.

2. Making of concrete and reinforced coverings

As well as in asphalt coverings, in the making of reinforced coverings an earth bed is made, a sub-foundation layers, a base of crushed stone and then polyethylene is laid, the reinforcement and the dilatation joints are mounted and then the concrete is laid. The same is vibrated by vibrating tampers or needle vibrators and is smoothed by lutes.
The ready concrete pavement is watered for a period of even, eight days. Samples are taken and are tested for strength and pressure.

3. Making of pavements

Upon the ready crushed stone covering a 3–5 cm layer of sand is laid and finely profiled by level, then the pavement is arranged densely over it. After the pavement covering is ready, it is profiled again by a statically passing roller- 5–7t. The joints formed are filled up with flushed or sifted dry sand.

4. Making of sidewalk borders, concrete strips

The sidewalk borders and concrete strips are arranged over concrete and using a thread. The base under the concrete is leveled and packed in advance. The joints between the borders are maximum – 15 mm.

5. Reverse Embankments

The reverse embankments are leveled and packed by small or big rollers, hand rammers with vibration by layers 20 cm thick. The reverse embankments are made of earth soil and rock mass.