Natural aggregate base stabilized with cement

NATURAL AGGREGATE BASE STABILIZED WITH CEMENT

CHAPTER 1

GENERAL DATA

Art. 1.  Object and scope of application

1.1.       These technical specifications comprise technical data regarding the execution of road bases made of cement-stabilized natural aggregates as well as the technical requirements provided under STAS 10473/1, that need to be complied with upon the preparation, transportation, laying and quality control of materials and of executed bases.

1.2.       According to the table constituting an attachment to STAS 6400, road bases made of cement-stabilized natural aggregates are used:

in the execution of upper foundation layers for:

Road of the I..IV technical class whose base is made of asphalt mixtures or cement-stabilized natural aggregates (second stabilized layer).

Roads of the technical class III and IV with bitumen covers whose bases are made of crushed stone wedged with illegible

Roads of the technical class I.III with covers illegible paving, with bases of cement-stabilized natural aggregates (second stabilized layer);

Roads of the technical class I.III with covers illegible cement concrete;

in the execution of the road bases of:

Roads of the technical class III.V with bitumen covers (without asphalt mixture layers);

Roads of the technical class III and IV with covers of illegible of block paving.

Roads of the technical class I.IV with bitumen covers (without asphalt mixtures layers) and of the technical class I.III, with paving covers whose foundations are made up of a lower layer of ballast and an upper layer of stabilized natural aggregates.

1.3. Cement-stabilized road bases can be also used:

-to widen the existing road foundations;

-to arrange platforms and parking places;

-to arrange parking lanes and framing lanes;

-consolidation of road shoulders;

Art. 2. General provisions

2.1.       In the execution of road bases made of cement-stabilized natural aggregates it is necessary to observe the provisions under the applicable specific standards and norms, to the extent these supplement and do not contradict these technical specifications.

2.2.          The contractor must ensure proper organizational and technological measures for the strict observance of the provisions hereunder.

2.3.          The contractor will ensure through its laboratories or through an authorized laboratory the completion of all tests and determinations indicated under these technical specifications.

2.4.          Upon Engineer's request of the Engineer, the Contractor must complete additional verification besides those specified hereunder.

2.5.          In case of any non-compliance with these technical specifications, the Engineer will interrupt the execution of works and will take all steps required.

CHAPTER II

TYPE AND QUALITY OF MATERIALS USED

Art. 3.                Cements

3.1.       In treating natural aggregates, one of the following types of cements will be used, type that has to comply with the technical quality requirements, as per the provisions under the respective standards indicated in table no. 1:

TECHNICAL QUALITY REQUIREMENTS FOR CEMENTS

Table 1

NOTE: Cements whose setting starts earlier than 2 hours must be used combined with a setting delayer.

Cements presenting mechanical resistance lower than the limits prescribed for the respective class will be declared and used only in a fashion that if proper to the new class.

In case cement is deemed to be altered, this will be removed as it is forbidden to use it in the preparation of concretes.

*cement II/A -S 32.5                conf. STAS 1500

*cement SR II/A -S 32,5                        conf. SR 3011

*cement H II/A -S 32,5                          conf. SR 3011

*cement I 42,5 (P 40)               conf. SR 388

*cement CD 40      conf. STAS 10092

3.2.       The site should be supplied from only one cement plant.

3.3.       In case the Contractor proposes the use of several types of cements it is necessary to obtain Engineer's approval.

3.4.       Technical requirements for the acceptance of cements must comply with the provisions under the respective standards.

3.5.       During transportation from the works to the concrete plant (or intermediary warehouse), manipulation and storage, cement will be protected against moisture and contamination with foreign bodies.

3.6.       Cement storage will be made in silo cells both in the case of auxiliary and consumption warehouses, compliant from the point of view of protection against alteration caused by meteorological phenomena.

Each cement transport will be stored separately so that is can be recognized and controlled.

3.7.       In the case of execution, whenever it is necessary to change the class of cement stored in the silos, the silos will be thoroughly cleared using the pneumatic installation and will be marked according to the new class of cement that is to be stored.

3.8.          It is forbidden to use cement at a temperature higher than +50⁰C

3.9.       The duration of cement storage must not exceed 45 days as of the date of delivery from the producer.

3.10.     The cement remained in the warehouse for a longer duration can only be used after verification of its preservation state and of mechanical resistances of 2(7) days.

3.11.     Quality control of cements on site will be made as per the provisions of table no. 6.

3.12.       The site laboratory will keep record of cement quality, as follows:

- in a file including all the quality certificates from the supplying plant;

- in a log (cement log) including the results of determinations carried out in the laboratory.

Art. 4. Aggregates

4.1.       Pursuant to STAS 10.473/1, for the execution of road bases made of cement-stabilized natural aggregates, the following classes of aggregates will be used, as indicated in table 2.

Table 2

4.2.       Aggregates must originate from stable rocks, that is imperishable in contact with the air, water or frost: it is forbidden to use aggregates originating from feldspar or schistose rocks.

4.3.          Aggregates must be inert and should not lead to damaging effects on the binder used in the execution of the stabilized road base

4.4.       Natural aggregates used in the execution of road bases stabilize with cement must comply with the quality requirements indicated in tables 3 and 4.

4.5.       Aggregates will be supplied in sue time to warehouses so as to ensure the homogeneity and constancy of the quality of these materials. Aggregates will be supplied to the concreting station only when the laboratory analyses have shown their compliance.

4.6.       During transportation from the supplier to the concreting station and during the storage, aggregates must be protected from impurities.

At the concreting station, aggregates must be stored on concrete platforms, divided into classes and stored in conditions that would prevent their scattering, contamination or mixture wit other classes.

4.7.       Quality control of aggregates carried out by the contractor will be made in compliance with the provisions under table no. 6.

4.8.       Contractor's laboratory will keep record of aggregate quality, as follows:

- in a file with all the quality certifications issued by the supplier;

- in a register with the results of determinations carried out by the laboratory.

Table 3

SAND, for the road bases made of natural aggregates stabilized with cement, used to execute the foundations of flexible road bases or of base layers (as per SR 662, point 2.3.2.1.)

AGGREGATES from the gravel pit or crushed quarry or ballast aggregates, for road base stabilized with cement.

Table 4

NOTE: 1. For heavy traffic roads and motorways, at least 50% of aggregates should be crushed.

4.9. Granularity, in any case, should be continuous and should comply with the limits indicated in tables no. 4 and 5.

Table 5

Square mash sieves as per SR EN 933-2, mm

See scanned original -pg 59

Granulometric area of aggregates for road base stabilized with cement

Art. 5. Water

5.1.       The water used to prepare the mixture of natural aggregates and cement can originate from the public network or from other sources, but in this case it is necessary to comply with the requirements provided under STAS 790.

Regardless of the source, at the commencement of works, a specialized laboratory will check water.

5.2.       When used on site, it is necessary to avoid water pollution by detergents, organic matters, oils, clays, etc.

Art. 6. Additives

The mixture of natural aggregates and cement frequently requires the use of set delayers. This might be the regular set delayer used in the preparation of cement concretes.

Art. 7. Protection materials

Cationic bituminous emulsion as per STAS 8877.

Sand class 0-4mm, as per SR 662.

Art. 8.  Quality control of materials before the preparation of the stabilized mixture

The materials intended for the preparation of road bases and foundation layers made of natural aggregates stabilized with cement are subject to preliminary tests and to determinations so as to establish the stability of network whose type and frequency are provided under table no. 6.

CHAPTER III

DETERMINING THE COMPOSITION OF THE MIXTURE OF NATURAL AGGREGATE STABILIZED WITH CEMENT

Art. 9. Preliminary tests

The study of the mixture of natural aggregates, cement and water will be carried out by a specialized laboratory by means of preliminary tests intended to determine:

- grain curve of stabilized aggregates;

- cement and additive ratios;

- water content;

-density in reference dry state, that is compacting characteristics.

Also, the preliminary test will determine the acceptable variations in the composition with a view to adapting it to the site conditions, preserving the features of prepared mixture in terms of workability, homogeneity and the featured required under point 10.2.

Art. 10. Composition of mixture

10.1. The stability of mixture's composition will be determined:

- at the start up of the preparing station;

- when the type of cement or aggregates is changed;

- whenever a reexamination of the composition used is deemed as necessary;

10.2. The composition of the mixture of cement, water and natural aggregates shall only be established by tests performed by a specialized laboratory, subject to the fulfillment of the requirements indicated in table 7.

10.3. Table 8 indicates the rough cement ratios.

10.4. The grain curve of the mixture must range within the limits indicated in table5. The grain curve selected is the one that leads to optimum physical and mechanical characteristics for standard compaction conditions (modified Proctor test).

10.5. As far as the water content is concerned, this has to be at the level of the optimum compaction humidity.

10.6. Compaction features, respectively the maximum density in dry state du_max and the optimum humidity Wopt of the layer made of grain material stabilized with cement will be determined by an authorized specialized laboratory, using the modified Proctor method, as per STAS 1913/13.

10.7.  In the case of stabilized natural aggregates, a special importance will be given to laying. This is the duration when the set is null and very weak and allows laying the mixture and its behavior without prejudice to the future mechanical features of such mixture.

The duration of laying required in the case of stabilized grain materials ranges from 2 to 6 hours according to the execution conditions. Such duration may be extended with 2 hours when set delayers are used.

The quantity of set delayer depends on the surrounding temperature that will be established by the laboratory as part of the preliminary tests, given that at 10⁰C the laying duration is estimated to be two times the one obtained at 20⁰C which in its turn is two times higher than the one for 40⁰C.

The test is run for various temperatures and a schedule of laying time-temperature will be drawn up.

Table 8

The cement ratio will be established by preliminary tests in such a way as to ensure the resistance (features) indicated in table 7.

CHAPTER IV

PREPARATION OF MIXTURES OF NATURAL AGGREGATES STABILIZED WITH CEMENT

Art. 11. Preparation station

11.1.     The mixture of natural aggregates, cement and water can be prepared in the continuous dosing and mixing plants or in the concrete plants, used for the preparation of road concretes.

11.2. The maximum distance between preparation station and the working point corresponds to a duration of transportation of natural aggregates, cement and water of maximum 45 minutes.

11.3. The preparation station must have:

a. aggregate warehouses with proper equipment for rain water drainage.

b. cement silos properly marked, whose capacity is correlated with the production capacity of the station;

c. preparation installation, with tanks and batchers in good working order.

d. bunkers where the prepared mixture is unloaded from the preparation equipment.

e. laboratory with proper arrangement and equipment.

f. equipment that ensure the washing of the mixer, bunkers and means of transport;

g. safety equipment and fire fighting and prevention equipment.

11.4. Preparation plants must comply with the following features, regarding the accuracy of weighting and dosing:

-aggregates                                 ±3%;

-cement and water                   ±2%;

-additives   ±5%.

Tolerances are expresses according to the weight of each component and must refer to the theoretical quantities as per calibration.

11.5. The contractor will provide the certification commission of the mixture preparation plant with the list of adjustments to be completed on the installation so as to comply with the requirements provided under art. 10, where this commission will control whether such adjustments were actually performed, that especially:

-calibration of volume batchers;

-verification of volume batchers;

-efficient operation of various shutting devices (opening-shutting) when aggregates, cement and water are introduced into the mixer of the preparation station;

-wearing of mixer's pallets;

Such verification will be completed before preparing the mixture.

Art. 12. Tests on mixture preparation

12.1. Before the commencement of works, the Contractor must perform tests on the mixture preparation station in order to check, using site means, whether the mixture formula established in the laboratory allows achievement of features required under the technical specifications.

Tests must be repeated until satisfactory results are obtained regarding:

- humidity

- homogeneity of mixture

-resistance to compression;

-optimum laying duration.

During such verification one shall also establish the minimum mixing duration that ensures a good homogeneity of the mixture prepared.

12.2. Samples used for verification shall be sampled from the mixture prepared during testing so as to check whether the features required are obtained, as indicated under chapter II, art. 10.

Art. 13. Actual preparation of mixture

13.1. It is forbidden to prepare the mixture in installations that cannot ensure compliance with the deviation provided under point 11.4, or where the dosing device they are equipped with are out of order.

The contractor is constantly liable for good operation of dosing devices, and has to check them whenever possible, but at least once a week.

13.2. The quantity of water necessary for the mixture will be adjusted according to the natural humidity of aggregates, so that an optimum compaction humidity is ensured during laying as established in the laboratory, taking into account the water loss during transportation from the preparation station to the laying location.

13.3. The quantity if cement put in the mixture is the one provided in the recipe established for each type of cement supplied.

13.4. The mixture of component materials will be made using the mixer of the preparation installation until the mixture is homogenous.

13.5. The mixture of natural aggregates, cement and water is introduced in the material storage bunker, from where it is unloaded in the motor truck, so as to avoid segregation.

Art. 14. Quality control of prepared mixture

14.1. The quality control of prepared mixture as well as the manufacturing of laboratory samples used to determine the physical and mechanical features of the mixture (compacting degree and resistance to compression) will be made as per table no. 9.

14.2. Contractor's laboratory will keep the following records regarding the quality of the mixture:

- composition of prepared mixture;

- compaction features - modified Proctor

- features of prepared mixture.

humidity : - at the preparation station

- at the laying location;

density of compacted layer;

- manufacturing of mixing laboratory samples and the determination of physical and mechanical features (resistance to compression and density) that will be recorded in the registered in the records.

Table 9

CHAPTER V

LAYING THE MIXTURE OF NATURAL AGGREGATES STABILIZED WITH CEMENT

Art. 15. Transportation of mixture

15.1. The mixture of natural aggregates, cement and water will be transported to the laying location using the tipping lorry (with backwards tipping) that circulates on the ballast foundation.

In hot or rainy weather, the mixture must be protected and covered with canvas so as to avoid any changes in its humidity.

15.2. The transport duration of mixture may not exceed 45 minutes.

15.3. The transport capacity must be compliant so as to ensure a continuous operation of the mixing installation and of the laying shop.

Art. 16. Preparatory works

Prior to the execution of the layer of natural aggregates stabilized with cement, one will accept the support layer as per the corresponding technical specifications.

Also, before laying, the support layer will be moistened, especially when this is made up of draining materials (eliminating any accumulations of water).

Art. 17. Tests regarding mixture lying

17.1. Before starting the works, the Contractor is bound to complete an experimental section.

The length of this sample section is of at least 30lm covering the entire designed width of the road. This experiment is intended to check on site, in current execution conditions, the execution of the quality features of laid mixture as per this technical specifications, adjustment of plants and of laying equipment, stability of compaction parameters (laying depth of mixture, compaction conditions and required compaction intensity).

All the data will be subject to Beneficiary's approval.

17.2. That portion of the completed section that is deemed to be best executed, will be used as reference sector for the execution of works on the entire road.

Art. 18. Laying of mixture

18.1. Laying and leveling

18.1.1. Laying and leveling of mixture must be executed in such a way as to meet the following requirements:

-observance of the accepted level tolerance for each layer separately;

-ensuring the width provided in the design for each layer, in all of its points.

-obtaining a proper surface.

18.1.2. Laying and leveling the natural aggregates stabilized with cement is made using the tractor grader or the mechanical vibration distributors.

The mixture is unloaded on the road in cordons and then, using the tractor grader or the mechanical distributors, this is distribute don half or on the entire way of the width as provided in the design, according to the adopted execution technology and to the type of works (reinforcements or new road systems).

18.1.3. Laying is usually made in one layer.

In the case of foundations, provided with width higher than 22 cm that are designed to be complete in two or several layers, laying shall be made as per the design provisions.

The maximum width of laying shall be established by the Contractor, on the experimental section, during the compaction tests.

18.1.4. Special attention must be paid to working longitudinal joints. The two adjacent layers that are executed in the same day must be completed in a two hours' time, so as to ensure continuity in the structure of the road base or foundation layer. The edge of the previously laid layer must be vertical. Cutting and removing the inside edges (towards the axis of the road and /where additional adjacent layers need to be completed) must be made in such a way as to ensure homogenous compaction on the entire length of the carriageway.

The resulted longitudinal joints, must be protected with polyethylene folios or with another similar material so as to avoid foreign bodies from penetrating into the joint.

18.1.5. In the execution of working cross joints, in order to obtain a vertical edge of the layer, the execution material must be cut and removed.

18.1.6. laying and leveling will be executed observing the design leveling quotas, and for this purpose marking will be executed outside the working surface, in the case of track grader leveling, or longitudinal beams and marks guards will be leveled for the electric detector finishers.

18.2. Compaction

18.2.1. The Engineer must witness the sample compaction on the experimental section. This one will carry out compaction control by laboratory tests, mutually agreed and carried out by a certified specialized laboratory.

The compaction equipment established as part of the sample tests completed, must be approved by the Engineer before being compacted.

The cylinder recommended for the compaction of natural aggregates stabilized with cement must have the following features:

Tandem cylinder with metallic wheels, vibrating strips whose minimum own weight is of 10 t on each cylinder;

Cylinder with tires with a minimum own weight of 18 t and with a minimum pressure in the tire of 5 bars.

Combined shops (metallic cylinder in the front part and tiers in the rear part0, might be used subject to Engineer's approval.

The compaction shop established on the experimental section will be indicated in the execution procedure approved by the Engineer and this will be observed on the entire execution of works.

18.2.2. In the case of execution of layers stabilized with cement in areas that are not accessible to compactors (especially along kerbs, around draining wholes or around manholes, road widening, etc), compaction will be made using vibroplates.

18.2.3. Compaction quality is assessed based on the minimum compaction degrees achieved that need to comply with the values indicated under point. 22.1.

18.2.4. In case the provided compaction degree may not be obtained, the Contractor will have to complete new tests after changing the width of the layer or the compaction plant used.

These tests are intended to determine the compaction parameters, that is:

-laying width before compaction in such a way as to  achieve the depth of the layer and the compaction degree required in the technical specifications.

-compaction requirements (checking the efficiency of the plant proposed and the compaction intensity).

The compaction intensity for a plant is the ratio Q/S where "q" is the volume laid in a certain unit of time (hour, day, shift) expressed in cubic meters and "S" is the compressed surface in the given time interval, expressed in square meters.

The Q/S ratio is experimentally determined and will be strictly observed along the execution. That is why it is indicated that the compaction plant should be equipped with a device that records data required to assess "S".

18.2.5. Obtaining such a high density requires that compaction is completed before the commencement of setting. This requirement may lead to the necessity to incorporate a set delayer in the mixture, especially during hot weather. The use of a set delayer is recommended so as to allow a correct execution of longitudinal joints.

18.2.6. The edges of the layers of natural aggregates stabilized with cement must be well compacted, together with the entire layer of stabilized natural aggregates.

Compaction will made as follows:

- compactor (without vibrations) will initially circulate at approximately 1/3 of its width on the shoulder and at 2/3 on the layer of stabilized natural aggregates.

-then the compactor (also without vibrations) will only pass over the stabilized layer in such a way as to push it under the shoulder, after which compaction continues regularly.

If shoulder compaction is only made before laying the layer of stabilized natural aggregates, steps must be taken in order to ensure water drainage on the entire surface of the road.

18.3. Measures in case of unfavorable weather conditions

18.3.1. The layers of natural aggregates stabilized with cement will be exceptionally executed at temperatures below +5⁰C, but only in excess of 0⁰C the Contractor and Engineer exercising a permanent and especially exigent control.

18.3.2. It is forbidden to use frozen natural aggregates.

18.3.3. It is forbidden to lay the aggregate mixture on a support layer covered with snow or with a ice layer.

18.3.4. The transportation of the mixture of aggregates will be made using fast means, thermo-insulated, avoiding high transportation distances and stops along the way.

18.3.5. After the execution of the layer of stabilized natural aggregates, its surface will be immediately protected by a canvas or rugs in such a way as to ensure a non-ventilated stationary air lock, 3-6 cm in depth, with a surface temperature of minimum +5⁰C, for 7 days.

18.3.6. At temperatures higher than 35⁰C, the surface of the layer of natural aggregates stabilized with cement will be protected with a bituminous emulsion applied in two successive layers.

Art. 19. Protection of road layers of natural aggregates stabilized with cement

19.1. In order to avoid water vaporization, the surface of the layer of natural aggregates stabilized with cement will be protected for at least seven days (during which there will be no traffic on this layer) using sand, approximately 1,5.3 cm thick that is maintained in a wet condition or that has a protection stratum made of:

-protection fluid: P45, STAS 12013;

-Polisol, as per the specific technical regulations in force;

-cationic bituminous emulsion STAS 8877.

The protection stratum will be executed immediately after compaction, on the fresh and moisturized layer.

19.2. If the base layer of the road structure is to be executed later, after having executing the protection for the foundation layer made of natural aggregates stabilized with cement, as per the provisions under point 19.1., so as to ensure a good connection to the base , a quantity of 7-8 kg/sq.m of chipping of class 16-25 will be laid, followed by a slight compaction  with tire compactor (ensuring the embedding of chipping into the foundation layer), operation that has to be done before the beginning of the set.

19.3. In the case of new road structures provided with bituminous covers and in the case of road rehabilitation, the base made of natural aggregates stabilized with cement will be protected as per the provisions of table no. 10.

Table 10

*) For roads with light and very light traffic and for road rehabilitation

19.4. In the case of rigid road structures, the foundation layer of natural aggregates stabilized with cement will be protected as per the previous provisions, the execution of cement concrete cover being started after a duration of 7 days.

19.5. When the foundation layer must bear a significant site traffic, the treatment with bituminous emulsion is not sufficient and a superficial treatment is to be applied as per the provisions of table 10.

19.6. The execution of the superior road layer may be started only after a protection period of minimum seven days form the execution of the layer stabilized with cement, period in which traffic is forbidden on this layer.

19.7. The layer of stabilized ballast will not be left uncovered in wintertime. Over the stabilized ballast layer at least the first layer of the designed road structure cover must be laid.

Art. 20. Quality control of the laid mixture of natural aggregates stabilized with cement

Quality control of the laid mixture of natural aggregates stabilized with cement will be made as per the provisions of table 11.

Table 11.

CHAPTER VI. TECHNICAL REQUIREMENTS. REGULATIONS AND VERIFICATION METHODS

Art. 21. Geometrical elements.

21.1. The thickness of natural aggregate layers stabilized with cement must comply with design requirements. The maximum thickness deviations are: -10 mm; +20 mm. Sub-base layer thickness is verified through direct measurements, at the edges of the executed straps, every 200 m.

The thickness of the layer is the mean of the measurements obtained on each section subjected to acceptance procedures.

21.2. The width of the natural aggregate layers stabilized with cements must comply with design requirements. The maximum width deviation is ±2 cm.  The execution width is verified at the transversal profiles of the design.

21.3. The transversal slope of the stabilized material layer must comply with design provisions. Maximum deviations of the slope may differ by ±0.4% from the value indicated in the design; the transversal slope is measured every 25 m.

21.4. Longitudinal declivities must comply with design provisions. Maximum deviations from design grades can be ±10 mm.

Art. 22. Compaction requirements.

22.1. Depending on the road technical class, the compaction degree of base and sub-base layers made of cement-stabilized natural aggregates must be:

at least 100% in at least 95% of measurement points and min. 98% in maximum 5% of measured points- for highways-, and in all measurements points for roads of technical class II and III.

Min 98% in at least 95% of the number of measurement points and min 95% in all measurement points for roads of technical class IV, V, for platforms, parking lots, stationing lane consolidations, road shoulders and traffic lanes.

22.2. Compaction features (maximum dry density; optimal compaction humidity) of base and sub-base layers are determined via modified Proctor test, in compliance with STAS 1913/13, and they correspond to the humidity section of the Proctor curve.

Art. 23. Features of the surface of the natural aggregate layer stabilized with cement

Surface irregularities are verified with the 3.00 m straight board template, as follows:

In a longitudinal profile, measurements shall be performed at the centreline of each traffic lane; the allowed irregularity tolerance shall be ± 10 mm

In a transversal profile, verification is performed at the location of the profiles presented in the design; allowed irregularity tolerance is ± 9 mm.

CHAPTER VII. ACCEPTANCE OFN WORKS

Art. 24. Acceptance of works at a determined stage

The acceptance of works at a stage determined in the design is carried out in compliance with Regulations concerning construction quality state control at determined stages of execution, approved via Government Decision 272/94, and in compliance with state control Procedures at determined stages of execution, drawn up by MLPAT and published in the Construction Bulletin Vol 4/1996. The determined stage acceptance of works shall be performed after all construction works indicated in the design documentation have been completed, and after all verification procedures have been concluded, in compliance with provisions of articles 8, 14, 20, 21, 22, 23.

The acceptance committee shall examine the works and check for compliance with quality and execution requirements, as stipulated by design drawings and by the Technical Specifications; the committee also verifies the reports registered during execution by the control entities.

At the end of the acceptance procedures, an acceptance Report for the determined stage shall be registered in the hidden work records; the report shall specify possible necessary repair works, execution deadlines for these repair works, as well as recommendations on monitoring road sections where provisions of the technical specifications hereunder have been breached.

Art. 25. Preliminary acceptance at the end of works

Preliminary acceptance of road layers made of natural aggregates stabilized with cement shall occur simultaneously with the preliminary acceptance of the complete road work, in compliance with the Regulations of acceptance for construction works and auxiliary installations, approved by the Governmental Decision No 273/94.

The acceptance commission shall examine compliance of the works with the approved technical documentation provisions, control documentation and acceptance report at determined stages, drawn up during execution of works.

Art. 26. Final acceptance

Final acceptance of base and sub-base layers made of cement-stabilized natural aggregates occurs simultaneously with the final acceptance of the entire roadwork, after its verification period has expired.

Final acceptance must comply with provisions of the Regulations approved by Govt. Decision No 273/94.

APPENDIX

REFERENCE DOCUMENTS

I. NORMS

MT Order No 43/1998: Norms concerning categorization of roads of national interest

MT Order No 45/1998: Technical norms concerning road design, construction and modernization

MT Order No 46/1998: Technical norms concerning establishment of public road technical class

MT/ MI Common Order no 411/1112/2000 Published in Official Gazette No 397/24.08.2000: Method norms concerning traffic interruption conditions and instructions for traffic restrictions necessary for execution of works in public road areas, and/ or road protection works.

NGPM/1996: General Work Safety Norms

NSPM No 79/1998: Norms concerning road and bridge exploitation and maintenance

MI Order No 775/1998: Norms concerning fire prevention and extinction, and technical extinction equipment.

NAR Order No 116/1999- Work safety instructions or road and bridge repair, maintenance and exploitation works.

II. TECHNICAL REGULATIONS

C54: Technical instructions for drill core concrete testing.

III. STANDARDS

SR EN 196-1: Concrete test methods. Part I: Determination of mechanical resistances

SR EN 196-3 + SR 196-3/AC: Concrete test methods. Part 3: Determination of hardening time and stability

SR EN 196-6: Cement test methods. Determination of fineness.

SR 662: Road works. Natural ballast pit aggregates. Technical quality requirements.

SR 667: Natural aggregates and processed stone for road works. Technical quality requirements.

STAS 730: Natural aggregates for road and railway works. Test methods.

STAS 1913/1: Foundation ground. Humidity measurement.

STAS 1913/13: Foundation ground. Determination of compaction features. Proctor test.

STAS 1913/15: Foundation ground. Determination of volume weight on the ground.

STAS 4606: Heavy natural aggregates for mortars and concretes with mineral binders. Test methods.

STAS 6400: Road works. Base and sub-base layers. General technical quality requirements.

STAS 10473/1: Road works. Natural aggregate layers or soil layers stabilized with cement. General technical quality requirements

STAS 10473/2: Road works. Natural aggregate or soil road layers, stabilized with hydraulic or pozzolanic binders. Determination and testing methods