The size of road slabs and the features of their installation

Concrete slabs or panels, commonly referred to as road slabs, are crucial elements in contemporary road building. They give cars a strong, level surface that requires less upkeep and guarantees a comfortable ride. These slabs’ sizes can differ depending on a number of variables, including the kind of road, the volume of traffic anticipated, and the local climate. Engineers can maximize the lifespan and functionality of the road by carefully choosing the right size and thickness of road slabs.

Road slab installation is an important procedure that needs to be carefully planned and executed. This include subgrade preparation, the installation of reinforcing elements, and the cautious pouring and curing of concrete. The installation procedure is made to cause as little disruption as possible and guarantee that the slabs fit together perfectly. In order to avoid common problems like uneven surfaces, cracking, and premature wear—all of which can result in expensive repairs—proper installation is essential.

Making sure that the expansion joints and alignment of the road slabs are correct is one of the most important aspects of their installation. Gaps between slabs known as expansion joints permit thermal expansion and contraction. Slabs could buckle or crack if these joints weren’t there because of temperature variations. Contractors also need to be mindful of the curing process because a poor curing process can weaken the slabs and jeopardize the structural integrity of the road.

Technological developments have also enhanced road slab installation. Time and labor costs are decreased by the more accurate and efficient installation made possible by modern equipment and methods. Precast slabs are one of the innovations that have gained popularity because of their dependability and speed of manufacture. They are made off-site and then transported for installation. These advancements aid in the construction of stronger, safer roads that can accommodate growing traffic volumes.

Types of road slabs

Road slabs are classified into two categories (per GOST 21924.0-84) based on their intended use:

• Intended for the construction of roads of permanent use (1P). In addition to the mandatory presence of loops, these products must be made of concrete with increased frost resistance (F200) and water resistance (W4).
• For the arrangement of temporary access roads (2P). In this case, it is allowed to manufacture products without the presence of mounting loops and recesses for them. Unloading/loading and installation are carried out using special collet grips. For this category, the requirements for concrete in terms of frost resistance (F150) and water resistance (W2) are also reduced.

Road slabs can be the following by geometric configuration (per the same regulatory document):

• Rectangular (P). They are most often used in road construction.

• Rectangular with one side (PB), which is designed for ease of joining with the curbstone. The side is located along the long side of the reinforced concrete product.
• Rectangular with two combined sides (PBB), located along the short sides of the product. Such slabs are intended for the construction of roads of fixed width.
• Trapezoidal (PT).
• Hexagonal (PS). Such slabs have the same thickness over the entire area.

• Hexagonal with increased thickness along the axial diagonal (PSHD). Also, for the convenience of docking with a curb, halves of such products are made (DPS).
• Hexagonal with increased transverse thickness (PSP). They also produce additional half products (PPSh), which are used to align the edges of the road surface.

Speaking of which, The exterior of the ZhBDP can be smooth or corrugated to enhance the wheels’ clutch with the road surface.

Given that the initial variety of ZhBDP is currently the most widely used, we will go into further detail about them here.

The dimensions of rectangular ZhBDP

The reinforcement technique used in the production of category P road slabs determines their overall dimensions. Goods featuring pre-tense reinforcement possess:

• thickness (h) – 140 mm;
• length (l) – 6000 mm;
• width (b) – 1750, 1870, 3000, 3500 or 3750 mm.

Reinforced concrete can also be made using non-stressed reinforcement. These slabs measure 1750 mm in length and 1500 mm or 1750 mm in width. Their thickness is 160 mm. Similar reinforced products with a thickness of 170 mm come in two standard sizes that are set in stone: 3000 × 1750 mm and 3500 × 2750 mm.

Marking of rectangular reinforced concrete panels

It is a combination of alphanumerics:

• First there is a number indicating the scope of application of the DP: 1 – for roads of permanent use; 2 – for temporary ones, respectively.
• This is followed by a letter corresponding to a specific type of product, characterizing its geometric shape. In our case it is P.
• The following are the nominal dimensions of the slab (length and width) in dm (rounded to the nearest whole number).
• The next number indicates the maximum load (it is indicated in tons). The slabs are produced based on the passage of vehicles weighing 10 or 30 tons.
• If pre-stressed reinforcement was used in the manufacture, then the type of steel used is indicated at the end of the marking.

The final product, for instance, has the marking 2P30-18-30. This indicates that it is meant to be used for building temporary access roads. Its dimensions are 3 meters by 1.75 meters and it can accommodate a vehicle up to 30 tons in weight. This slab was made using non-stressed reinforcement and has a thickness of 170 mm in compliance with GOST.

One more instance is 1P60-19-30AV. Permanent roads are built using this type of reinforced concrete. Its overall measurements are 6 m in length, 1.87 m in width, and 0.14 m in thickness. A vehicle can only weigh a maximum of 30 tons. The manufacturing process employed grade A-V steel pre-stressed reinforcement.

Pros and cons of laying a road from precast reinforced concrete slabs

• No careful preparation of the base for laying RC slabs is required.
• Low cost of the materials used.
• Reinforced concrete has high strength, frost resistance and resistance to significant temperature changes. Therefore, they can be used practically throughout the entire territory of the Russian Federation.
• The technology for laying such a road can be implemented on any soil (even on marshy terrain).
• Possibility of multiple use of reinforced concrete slabs.
• Installation of slabs does not require much labor and can be completed in a short period of time.

• To extend the service life of reinforced concrete slabs, they can be covered with a thin layer of asphalt at the final stage.
• The access road can be used either immediately after the completion of the road construction (if only sand was used to seal the joints between the slabs), or after 48 hours (if wet sand-cement mortar was used).
• Use of products in a wide temperature range – from -40 degrees Celsius to +

Even with all the benefits, there is one significant disadvantage to consider. A road like this is a constructor made up of numerous pieces that are placed on the ground. Significant gaps between the slabs may form and the overall geometry of the laid road surface may alter as a result of soil movement over time.

Be aware that in order to keep an already built road from being destroyed or having its performance qualities reduced, it must be continuously inspected, and any damage found must be repaired right away.

Methodology for laying road slabs

The following is the order of work:

• Preparatory actions. Make markings of the future road. Remove the top layer of soil using special equipment (for example, an excavator).
• Dig a trench, the depth of which varies from 250 mm to 500 mm. This depends on the type of soil, for example, if the soil is clayey, then you should go deeper.

Crucial! First piece of advice: planning drainage is important if the road is intended to be used permanently (an excavator will also be required for this). The second piece of advice is to never lay road slabs on the ground directly. This is dangerous because the road will be destroyed and they will eventually subside.

• Carefully compact the soil at the bottom of the trench. A vibrating plate is used for this purpose.

Take note: You must keep an eye on the soil level. A level or a rope that has been stretched to the necessary height is used for this.

• To prevent the cushion, which will be arranged later, from being washed out, geotextile is laid on the bottom of the trench.
• A “cushion” is poured on top of it, which is a layer of crushed stone (about 100 mm) and a layer of quarry sand (about 200 mm). The height of the backfill can be greater: it depends on the loads that the slabs will have to bear, as well as the type of soil.

Reminder: Cement and sand should be combined to strengthen the "cushion." This kind of road arrangement allows driving only 48 hours after it is made.

• Next, the “cushion” is poured with water. This must be done without fail so that there are no voids left in the backfill under the reinforced concrete slab.
• Then the sand layer is thoroughly compacted using a vibrating plate, roller or hand rammer. This is done layer by layer. If depressions or dips are noticed, the required amount of sand is added to them.

• One by one, the road slabs are mounted on the “cushion”. It is unlikely that you will be able to do without lifting equipment at this stage. After the product is mounted on the sand, a thick board is placed on top of it, which is hit several times with a sledgehammer. This is done so that the entire surface of the reinforced concrete slab is pressed against the “cushion”. To avoid any distortions, the outer row of road slabs is mounted along the cord stretched during marking.

Be aware that the technology enables end-to-end or small-gap slab installation.

• Gaps between the laid slabs are filled with either sand or a sand-cement mixture. When using the first method, the material must be generously watered so that it is thoroughly compacted. When using the second method, it is imperative to fasten the mounting loops of the reinforced concrete slab together using welding.
• For the final alignment of the road surface, a layer of asphalt is sometimes laid on top of the slabs.

Building sturdy and effective roads requires an understanding of road slab sizes and installation procedures. Road slabs are available in different sizes, each appropriate for a range of traffic volumes and environmental circumstances. For the road to be stable and long-lasting, the slab’s size and thickness must be properly chosen. Planning and designing properly can help prevent common problems like settling and cracking, which can result in expensive repairs and traffic disruptions.

Road slab installation requires meticulous planning and execution. In order to support the slabs, it starts with evaluating the site and creating a strong base. The required strength and durability can be attained during installation by using the right materials and techniques. As part of this process, the slabs must be properly aligned and spaced apart to allow for temperature-related expansion and contraction. Reinforcement and control joints can also be added to improve the road surface’s functionality.

To sum up, choosing the right size and adhering to best practices during installation are critical factors in determining how effective road slabs are. Engineers and construction teams can design roads that are resilient to high traffic volumes and changing weather conditions by giving priority to these factors. In addition to extending the life of the road, investing in high-quality components and exact installation methods creates a more dependable and safe transportation system. All things considered, a well-done road slab installation is an essential part of contemporary road building that helps communities by supplying durable, effective roads.

The size of concrete slabs is a critical factor in ensuring smoothness and durability when building roads. The lifespan of the road can be increased and the risk of cracking reduced with the right slab dimensions. The kind of traffic, the weather, and the stability of the soil must all be carefully considered during the installation process. To account for natural expansion and contraction, this requires careful planning and execution, as well as the use of reinforcements and control joints. Comprehending these elements is crucial for constructing roads that are efficient and safe even under extreme conditions and traffic volume.

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