New Quality Control Laboratories Commissioned on M-12

Stroytransgaz Group is carrying out the construction of Phase 1 of the M-12 Moscow-Kazan-Ekaterinburg Highway. In early April, QC laboratories were commissioned to control the quality of produced asphalt mix, and, in late April, placing of asphalt layers started.

On April 28, a media tour was organized at the construction project sites. Journalists were shown how the new quality control laboratories and asphalt concrete plants are operating, the asphalt laying process and construction of crossing structures at station 283 and at the bridge across the Kirzhach river was explained in detail.

The new quality control laboratories are functional units that carry out various investigations in order to test the quality of all construction operations and materials used. Such quality tests include the following procedures: testing, measuring, investigation, diagnostics, objective evaluation, documented assays.

The main purpose of a test laboratory is to conduct a comprehensive examination of incoming material, with focus on end product quality. Laboratory functions include:

- Testing and quality control within the accredited scope;

- Preparing organizational and administrative documents;

- Selecting and approving formulations of asphalt concrete mixes in terms of materials used;

- Certification of selected quarries supplying non-metallic materials (sand, crushed stone, crushed stone-and-sand mixes, sand-and-gravel mixes etc.);

- Material sampling;

- Measuring and testing to evaluate conformance of materials to quality standards;

- Final measurements and tests to evaluate conformance of products arriving at the construction site to quality requirements of the design documentation, applicable codes and standards, accompanying documentation, supply contract;

- In-service quality control of construction and installation operations.

The laboratory is fully equipped. Here are some examples of the key laboratory equipment:

- Muffle furnace is used to determine the granulometry of asphalt concrete mix. Samples are taken both at the asphalt concrete plant and when designing a formulation in laboratory conditions from a electromagnetic lab stirrer. With the furnace, you can obtain test results within 3 hours, which is sufficient for on-line testing of mix granulometry. This indicator is extremely important, because mineral aggregate makes up the matrix of an asphalt mix.

- A gyratory compactor is a rotary compactor that can compact an asphalt concrete mix. This device compacts the mix thereby closely simulating the operation of compactors in the field.

- Rutting test machine. It simulates transport load on the asphalt concrete pavement. Thereby pavement quality can be tested according to GOST requirements.

- Los Angeles machine is designed to make abrasion tests of inert materials. Some tests can be carried out within 2-3 hours, including specimen preparation time, but many require long hours and physical strength.

There are different types of laboratory tests. Operational tests are carried out directly in the field (this is instrumented inspection: visual, thickness, width, temperature). Receiving inspection is acceptance of all inert materials: geosynthetics, bitumen, emulsion, mineral powder, concrete items etc. Acceptance inspection is handover of the end product, i.e. asphalt pavement in our case.

During the peak season, 4 asphalt concrete plants will be operating at Phase 1 of the M-12 Highway. 2 of them were put in operation last year, and another 1 is planned to be put into service in early May 2022. The fourth plant will start operating in summer. Overall, the plants will produce 500 tons per hour.

Two plants will be located at "Pokrov" operation base and the other two near the village of Vasilyevka. Each site will have a QC laboratory to test quality of the asphalt concrete mix produced by the plants.

At Phase 1, the 14cm-thick top layer of base course is now being laid. Progress now is 12km. With production ramping up, it is expected to place 4,000 tons per day. For paving, SP 32-E asphalt mix is used, which is suitable for roads with heavy traffic and designed for extreme loads. It contains a unique binder designed specifically for climate conditions in Moscow and Vladimir Regions.

Next, the bottom and top layers of surface course will be laid. Over 2022, it is expected to place about 640,000 tons of asphalt mix during Phase 1.

Phase 1 of the M-12 highway construction project will include building 29 crossing structures, which are 24 bridges and overpasses, 3 cattle passes, and 2 pedestrian underpasses. During the media tour, journalists were shown the bridges over the Kirzhach river and over the swamp at station 283.

The bridge over the Kirzhach river is one of the longest bridges at M-12 Phase 1. It is situated near the town of Gorodishchi. The bridge is 268m long and 24.6m wide. It will rest on 8 piers. To date, 6 piers have their piles driven to full depth. Current operations at the site are installation of pile cap and cutting of pile heads on pier 6, driving of pier 4 piles, and installation of a slipway for pre-fabrication and launching of steel superstructures.

This bridge is unique in that this is the only location where a hydraulic static pile driver is used, a machine rarely seen in road construction. The use of impact hammer equipment is not allowed here because the bridge is too close to an operating gas pipeline. This pile driver uses its own dead weight to drive piles into the ground rather than applying additional vibration or impact. Even though the hydraulic static pile driver is quite large and has no wheels or tracks, it can easily move around the construction site (literally, it can walk).

The bridge over the swamp at station 283 is situated between the Chyornaya River and the Tanka River, which is close to Omutishche railway station of the Gorky railway line. Building a crossing structure at this section was not in the initial plan. Initially, it was planned to drain the swampy grounds, then construct the roadbed embankment and lay the motor road. After additional geotechnical investigations that identified hidden karst sinkholes, it was decided to design and then build a bridge at this section.

A 147m-long and 24.6m-wide bridge will now be built at station 283. It will be constructed on 4 piers using bored piles enclosed in steel shell. They will vary in length from 24 to 28.3m, with diameter of 1.42m. The steel-and-reinforced concrete superstructure will be launched from the slipway onto the piers. The total weight of steel for the superstructure will amount to 827 tons.

Builders are now driving casing pipes on piers 3 and 4 at the bridge site. On the slipway, casing pipes are being jointed into larger section to be then driven in the ground. 12 test piles of the embankment foundation structure have been completely driven and dynamically tested. The work on this crossing structure began in March 2022 and is expected to complete in less than one year - in January 2023.

This bridge is unique in that it is the only one at Phase 1 of the M-12 construction, where bored piles are used and total 132. Two 100-ton crawler cranes and one 300-ton crawler crane are used to install bored piles at the locations of piers 3 and 4. Vibrodrivers and hydraulic hammer with a 7-ton ram mounted on the cranes are used to drive casing pipes and then install bored piles.

About 1,880 people and 460 units of machinery
are used in the construction of M-12 Phase 1 every day.