Construction of M42 NEC bypass

Construction of bypasses has various impacts on the local communities, which can be either positive or negative. The effect of bypass construction social, economic, and political. Studies have shown that opening new traffic routes results in land-use changes and land development. It also imbalance ecosystem, a shift in travel behavior, spur economic growth, and other impacts, such as shifts in levels of businesses, noise, and pollution (environmental concerns), has implications as shifts in business levels, and reduce traffic congestion. In this section, this report discusses impacts businesses cases of M42 Bypass to the local communities.

Positive Impact

Although several impacts of bypass construction on the population have been reported, it is not easy to relate population changes to one particular Bypass. The population trends that have been observed are basically long-term and this is due to the fact a number of studies depend on the decennial data to make conclusion regarding population change. However, generally, the bypass areas tend to be densely populated.

Usually, there is a general growth in business activities following a construction of a bypass. Often, there is the period of transition that decline the relocation of services that depend on traffic or sales of petroleum products, such as gasoline, fast food among others. As a result, there is higher business growth in downtown areas as a result of decreased levels of pollution, noise, and congestion. In general, there is an overall growth of community business activities through gross annual sales (total revenue). This rapid growth is due to bypass construction.

Whenever there is a bypass, values of land tend to increase, which in turn help to thrive business activities along the Bypass. Costs of land increases because bypasses tend to influence land access, especially in somewhere the new Bypass passes through. Therefore, the value of land, as well as land-use practices, usually show significant changes.

Negative impact

Construction of bypasses can also do businesses in older routes that are bypassed to suffer sales losses. This observation is attributed to adverse changes in the economic and demographic trends and the decline in sales in these ancient routes. Generally, the construction of bypasses destroys the natural habitat for wild animals. Habitat destruction leads to a change in the population, especially birds. The reason being birds are susceptible to habitat disturbance and ecological changes, mainly diurnal raptors (Sabol, 1996). For example, eagles have profoundly been affected by human activities, such as road construction, especially those that go through parks.

2.1 Construction of Road Embankment

For many years road embankments have been used to divert or impound flood flows. Embanks involve the construction of simple compacted structures that are used to resist overturning and sliding using their mass. Therefore, an embankment can be defined as an earthen material volume heaped and trampled together when constructing a dam, a road, a rail, its primary purpose is to raise, for example, a roadway grade above the existing surrounding ground level. Usually, wherever there is embankment there fill. A fill can be defined as the earthen material volume that is heaped and compacted to be used later for depressions or holes filling. Therefore, the construction of fills or embankments is compost of soil materials, including crushed paving materials, rock, or aggregates.

During road construction, engineers usually place coarser fill materials near or at the embankment’s base or bottom to build a firm embankment foundation and prevent saturation by facilitating drainage. Engineers generally construct the upper part of an embankment to be of high-quality using sub-grade materials, which are well-compacted with the ability to support layers of the overlying pavement as well as the imposed loadings of wheels without unwanted movement or deflection. As such, the fill material that is applied through the entire remaining parts of the embankment must meet the required quality specifications quality. Besides, the materials must also be compactable close to or at its maximum density. This process is achieved by spreading the material in thin layers of 150 mm-200 mm, in which heavy rolling equipment is used to compact every layer (Debbarma et al., 2019).

Various soil types are suitable for use when constructing an embankment; these range from gravel and sand (granular soils, which are the most desired soil types, to silt and clay (fine-sized soils) as the least desired soil type. Highly organic soils and saturated clays are considered as unsuitable soil types or materials for constructing an embankment. Irrespective of the soil type used in the construction of an embankment, the material must be within the correct moisture for optimum compaction, must be compactable, well-graded, and should not contain harmful or unsuitable materials like trash, metal, sludge, stumps, branches, and tree roots. The base of embankments can also be constructed using oversize materials, materials whose size is more than 100 mm, for example, air-cooled bags, reclaimed paving materials, large stones, and rocks. These oversize materials used should be strong enough to overcome the weight of construction equipment or machinery when constructing the embankment.

Embankment Construction Method: Staking

Before any activity of construction starts, engineers must transfer the design information from the paper plan to the ground, a process that achieved through staking. The most effective way to ensure design standards compliance is through effective use of slope stakes to keep soil disturbance to a minimum. There are different methods of staking that can be used to construct road embankment (Koglin, 2016)

In this paper, we describe how staking as an embankment construction method is used to mark different design points of a road using stakes; that usually eradicated during the phase of clearing and grubbing. Relocating stakes, such as slope stakes or centrelines, helps engines establish points of reference in the external parts that are off the clearing zone. Usually, behind uphill clearing limits, the construction of embankment points of reference should be set not less than 5 meters. Reference points on the average are generally set between 70 meters to 100 meters, where it is possible to re-establish an alignment of the centreline, for example, points of curvature, as shown in fig. 1.

Fig. 1. Construction of information of a road embankment construction cross-section. FAO (2018)

The machine operator uses stakes to locate points to start cutting before starting to construct an embankment. For cutting points that are too high, then massive earthen materials have to be removed to ensure a proper subgrade construction, as shown in fig. 2. If a cut results in a 20% wider subgrade, for example, say about 50%, then more volume will have to be excavated. For a shallow cut, the other side would be overstepped by cut casting to avoid having undesirable embankment. Thus, it essential to start the cut at an appropriate point as the side slope increases. In other words, it essential to set slope stakes when side-slopes go beyond 40%-45%; however, this depends on the area’s sensitivity and experience of the operator.

Fig. 2. Showing the impact of an improper cutting start as the slope stake demarcate-there is excess side cast and excavation due to too high cutting. FAO (2018)

The application of slope stakes or reference points is useful when one wants to achieve appropriate embankment excavation, as shown in fig. 3. In this instance, the architecture or engineer determines the reference point by standing on the preliminary construction-grade centreline. The engineer then records 5.53 m slope distance and of a 30% slope reading. The next step involves converting the 5.53 m slope distance to a 5.30 m horizontal distance then to a 1.59 m vertical distance. Through these calculations, the engineer can determine the amount of preliminary or present centreline to shifted to achieve the desired design. In this case, the reference point tag would require a 6.50 m horizontal distance to centreline with a 4.80 m vertical drop. Based on this information, it is clear that there is an additional distance, for instance,

The additional must be cut; thus there is also a need to shift the present location by;

In this case, it is assumed that the eye-level or height of the instrument is 1.65 m.

Fig. 3. Checking of a road embankment construction grade. FAO (2018)

Geology of the area: Near M42 (with an estimated location for the junction)

The area near M42 required a depth till between 3.0 meters and 5.0 meters because, at this point, the foundation of road construction would be shallow. The geological analysis of the area revealed that to it west, there were superficial deposits of sand and gravel, Mid Pleistocene, and deposits of Glaciofluvial. Also, there superficial deposits of sedimentary soils formed during the Quaternary period around 860 and 116 thousand years ago. On the eastward side of the site, soil type is made sand and gravel, silt, and clay (alluvial deposits) with superficial deposits of sedimentary formed the Quaternary period, 11.8 thousand years ago. On the M42 Solihull section, that is to the east of M42 is the first Borehole where the topsoil is tilled to 0.15 meters below the ground level beyond which the soil becomes firm and hard with red mottled silty CLAY up-to 2.2 meters. The activity will involve excavation of natural land, fill and construct embankment with local same type soil. A 20 degrees repose angle of silty clay, which is a stiff-solid where the height of the design embankment used would be 3 meters. Given that width of the embankment is 3.58 meters, then the height of the is calculated embankment;

Hence, 8.24 meters would be capable of holding the embankment slope at a degree of 20 degrees, thereby providing embankment slope with uniform degree throughout the entire route; the Borehole map would be as shown below.

Borehole Map

Fig. 4: British geology and Map of Borehole

2.2 Compaction and Consolidation Work in Pavements Construction.

Pavement construction in the current world is being performed effectively and efficiently than ever before. Pavements are constructed smoother than ever before, offering an excellent riding surface, which can retain a proper surface texture, and that is skid resistant. The advent of stringiness trimming and paving has made the construction of pavements more efficient. Laser and optical guidance systems have also predominantly contributed positively to the construction of pavements. The application of well-graded concrete mixes has indicated good properties in the hardened state, enhancing durability and performance. They can also be applied in fresh state aiding constructability. Some basics are applied to the understanding of the basics in pavements construction. The following are the basics that are applied in the construction of the pavements (Debbarma, Ransinchung R.N. & Singh, 2019).

Subgrade Preparation

Construction of quality pavements’ initial stage involves the preparation of the soil surface adequately. Existing soils must be compacted and graded properly to correct the elevation that is appropriate for the project. The construction process involves the placement of a base layer material on top of the subgrade. In the placements of fixed-form pavements, the equipment that is applied is the float, straight edge, and tube roller. They are used in the striking off and finishing the concrete surfaces. The subgrade soils do influence the pavement design to be applied. Besides, it determines whether the construction work will involve placement of cushion in the base material during the construction works. This aids in cushioning the slab applied in the pavements. This method is majorly effective on certain clays that extremely susceptible to changes in moisture, expands when wet, and shrinks whenever they dry.

Various kinds of graded stones can be used as base materials, including, quarried stones, crushed stones, and rounded river gravels. Additionally, any other material which can be used to attain an excellent density with minimum voids as possible when compacted. The material to be applied needs to stable but not necessarily dense. Some construction workers rework the soft spots in the subgrade material, mixing hydrated lime, as this helps in drying the material and binding it together. Besides, hydrated lime often acts as a binder to stabilize the soil and dry up muddy and soft spots.

Ensuring the Use of Quality Concrete

The concrete applied for the pavements’ works must be planned in a manner such that they reach 4000 psi compressive strength at one month. Besides, a more desirable characteristic of concrete should be durability. The concrete applied must stand up all kinds of weather dry or wet. One way that contributes to durability is quality aggregates a well-graded mix. The entrainment protects the concrete when freezing happens. The tiny bubbles prevalent in the concrete mix serves as air valves whenever freezing takes place. Air entrainment also serves great importance through making the concrete more workable. Naturally, existing concrete contains air bubbles, but when well-controlled, it can help in ensuring that the construction work is more comfortable. It is also essential to realize that concrete contains water during its entire lifespan. These bubbles do not fill with water since the water is located in the other parts of the concrete microstructure.

Slump measures the fluidity and workability of the concrete. An excellent workable pavement mix for fixed-form construction will have a slump with a thickness of 4 to 5 inches. If the slump of a batch of concrete is extremely low, adding water is not a solution. Chemicals can be added to make the mixture more workable without impacting the strengths of the concrete or causing all the adverse aspects that come across as a consequence of adding water. If the slump turns out to be too low and the mixture too stiff, water-reducing admixture can be used to increase the slump without applying water. Additional water can improve the water-cement ratio that should be maintained at 0.45 or even lower. Higher water-cement ratios have an adverse effect as it deteriorates the durability of the concrete.

Placing and Finishing

A proper application of the curing compound is important for preventing water from evaporating during the curing period. The rest of the steps in fixed form the pavement construction include finishing and curing. Even though a significant number of highway pavements in the current world are placed with a slip form paving machine, the most commonly applied form of concrete pavements construction is still the fixed-form work. It fundamentally involves simple as setting 2*4 pavements as the side forms. Completing the concrete surface is the kind of setup that can be equally simple when screeding with a 2*4 with vibrating screeds. The best way to spread the concrete is the use of truck chute, maintaining a consistent level in front of vibrating screed or straightedge.

Following the initial strike-off is the waiting period for the bled water to rise the pavements texture should be enhanced. This is achieved through three different means. First, a broom can be applied to texture the surface. Another way is the application of wet burlap that is dragged on the surface. Finally, artificial turf may be used when turned upside down and dragged on the top surface of the pavements. A high –traction texture is applied on the pavement of the surface to eradicate the slick surface.

Importance of Curing

After the constructors are through with the texturing process, a layer of wax-based, membrane-forming curing compound to be sprayed on the surface. Upon drying, the membrane seals ensure that the concrete near the surface will not dry without enough hydration. Failure to cure the slab without enough hydration, the water around the surface will evaporate rapidly without complete reaction with the cement leading to the surface of the concrete being lower-strengthened. Thus, failure to purely cure the surface of the pavement will render the pavement to be less durable. Other means of curing may include fogger, sprayer, or sprinkler. Curing compounds tend to be quicker, easier to use, and more reliable (Wang & Wang, 2013).

Joints Key to Control Cracking

It is essential to form a cutting edge on the pavement as the last stages of pavement construction. The major aim of applying joints is to control the cracking nature of the pavements. Lack of applying joints would eventually lead to the cracking of the pavements due to the shrinking that occurs on the pavements.

Importance of Compaction

Compaction of the top pavement is essential in the construction of the pavements. Compaction can be defined as the process through that the volume of air in the HMA mixture is minimized. This process is facilitated through the use of external forces. The reduction of HMA volume air consequently leads to an increase in its density. Measurement of air void content is applied in determining the effectiveness of the compaction. The assessment is expressed as a volume in terms of percent air voids of the compacted mixture. Calculation of the percent air voids is done through the application of Tex-207-F and Tex-227-F. This process applies a bulk specific gravity and a maximum theoretical specific gravity (also referred to as Rice gravity) in the following equation: There are several advantages of applying compaction. Some of these purposes are discussed above as decreasing stiffness and reduction of fatigue life.

Equipment Applied

Two means can be applied to densify HMA in the pavement construction. These methods are also generally referred compactive effort. Some of the equipment are steel wheel rollers, pneumatic tire rollers, and paver screeds. Besides, other forms of vibrators may also be applied (“PCC Consolidation – Pavement Interactive,” 2020).

References

Debbarma, S., Ransinchung R.N., G., & Singh, S. (2019). Feasibility of roller-compacted concrete pavement containing different fractions of reclaimed asphalt pavement. Construction And Building Materials, 199, 508-525. doi: 10.1016/j.conbuildmat.2018.12.047

FAO (2018). CHAPTER 6 ROAD CONSTRUCTION TECHNIQUES. Retrieved 3 May 2020, from http://www.fao.org/3/t0099e/T0099e06.htm

Koglin, T. L. (2016). High-Speed Rail Planning, Policy, and Engineering, Volume I: Overview of Development and Engineering Requirements. Momentum Press.

PCC Consolidation – Pavement Interactive. (2020). Retrieved 3 May 2020, from https://pavementinteractive.org/reference-desk/construction/placement/pcc-consolidation/

Sabol, S. A. (1996). Effects of highway bypass on rural communities and small urban areas. Research Results Digests, NCH Program, Washington, DC.

Wang, H., & Wang, Z. (2013). Evaluation of pavement surface friction subject to various pavement preservation treatments. Construction And Building Materials, 48, 194-202. doi: 10.1016/j.conbuildmat.2013.06.048