Goal
The construction of the Waikato expressway involves a resource consent application majorly on the assessment of environmental impacts. The New Zealand Transport Agency was the main commissioner of the construction of this expressway with the aim of reducing traffic, travel time while providing connection between different roads and stations.
The aim of this study was mainly to establish the quantification of the impacts of the construction materials, processes, and equipment on the environment. The researcher aimed at attributing the LCA for the Waikato Expressway at Hamilton between Lake Rd and Tahamere interchange on the fuel consumption and CO2 emissions. The report from this research will be addressed to the environmental management and construction industries to enhance environmental sustainability through reducing emissions and inappropriate waste discharges.
Scope
The Waikato expressway covers 22 km from Lake Rd to Tahamere and it will be of great importance in various ways such as reducing traffic. The construction rate is 5 km per day where all the equipment is in use for 10 hours each per day. The construction work is defined in terms of the distance covered per day in km, the amount of soil excavated, tonnes of stone aggregate, and amount of CO2 from the fuels and rock processing. The construction of the express way will take more than 3 years and it will involve several steps and processes which are essential for the completion of a quality highway.
These processes will include transportation of materials and waste discharges to the site and out of the site respectively, rock processing to produce stone aggregates, excavation, installation of steel, concrete pouring and bituminous layering (pouring asphalt, surfacing and leveling). The boundaries involved in the construction will be from excavation, transport of materials through to bituminous layering. Under the allocation amount (mass) which involve the amount of land for construction and for the dumping site and economic in terms of finance (funding of the project). The main environmental impacts from the construction of the expressway are the emissions of CO2, dust particles, PAHs and sulphur. The LCA for this project involved consequential (step by step assessment of processes) and economical assessment (allocation and funding) with respect to environmental impacts. Since the main of the study was to quantify environmental impacts, the data obtained will be interpreted in terms of the amount of CO2 emissions, fuel consumption and energy used. From the various sources such as journal articles and books the data recommended for this study is both qualitative and quantitative.
There are several assumptions that were made in this study although it does not affect the quantification of CO2 emissions. Based on the data provided was not adequate enough to proof the quantification of CO2 and dust particles since some of the aspects like energy and amount of burden were not factored in during calculation. Since several assumptions were made, various estimation was done hence not providing adequate information to quantify emissions data. Required data should conform to the modern/current state of equipment and process of construction, available on the NZ transport website and should be relevant in terms of carbon dioxide emission. The transport agency should check the quality of the data to check whether it is relevant to calculation of the environmental impacts. A technical report of this study will be presented to establish how much construction Waikato Expressway has impacts on the environment.
Material flow and assumptions
The required materials were supplied on regular basis and on time to ensure continuous flow of construction while ensuring there is no congestion in the construction site. The various stages and processes that were involved determined the flow of the materials to the site. Several assumptions were made from the first step to the last while taking into consideration the objective of the project with respect to environmental impacts. These include:
- ignoring of overburden removal
- ignoring the amount of energy used
Steps and Processes
Waikato Expressway is an essential road connection which was constructed to reduce traffic along the road as well as reduce travel time between different stations. Several processes were involved in the construction of the express way with respect to reducing environmental impacts from the construction. Surveying is done during every step using total station and theodolite to ensure that the work is quality and that less steel and concrete are used to reduce environmental impacts.
| Steps | Processes | Equipment |
| Transport of materials and waste | · Transportation of Cement, rocks, steel, tools, and sand to the construction site · Transport of discharge waste from the site to the dumping site · surveying | · trucks and dump trucks · tippers · total station |
| Rock Processing | · Crushing of rocks · Sorting of rocks through classifying based on grades · Various grades are transported to the piles · surveying | · classifier · rock crusher · belt conveyor · trucks · total station and theodolite · mineral filler |
| Excavation | · surveying ground levels · depth excavation · covering and compressing the loose soil · constructing trenches · making boundaries of the way · bunds and drains construction · surveying | · excavators · bulldozers · tippers · graders · fork lifts · theodolite |
| Installation of steel | · lifting and placing components · structural aligning · bolting-up · surveying | · cranes · fabricators · theodolite and total station |
| Pouring concrete/asphalt | · Grading and sloping · bindering and surface coursing · proof roll, undercutting and sub base repair · butt joints and transitioning | · mechanical spreader · multi tire roller · Automatic motor grader · quad-axle dump truck · compactor |
| Bituminous layering | · surface treatment · dense surfacing · asphalt rolling · surveying | · bitumen sprayer · asphalt distributor truck · theodolite |
At every step the engineers takes into consideration how the construction impact the environment. In need to reduce the environmental impacts, preventive measures are put in place to ensure that the processes involved together with the equipment used ensure environmental sustainability. From the table above, it can be shown that there are various steps, processes and equipment used in road construction. It is no doubt that these aspects affect the environment negatively. The LCA of the project on construction of Waikato express way shows that from the first step (transportation of materials and waste) to the last step (bituminous layering) effects from the construction of the road can be negative. During excavation of the site pollution of the environment is enhanced due from the fuel emissions and dust particles. Careful maintenance of excavation and damping down can reduce these impacts if the contractors consider applying. Appropriate disposal of waste materials from the site is another mitigation measure to reduce construction environmental impacts. Actually, the engineers and the contractors should take appropriate mitigation measures to curb negative environmental impacts.