• Based on socio-economic cost-benefit analysis, concrete roads provide superior returns on social capital outlays in the medium to long-term basis
The ongoing debate between concrete road construction and asphalt road construction in Nigeria has gained significant attention due to current circumstances. This discussion revolves around key factors such as durability, cost-effectiveness, maintenance, and environmental impact. Each method has its advantages and disadvantages, leading to a careful consideration of multiple factors before making a choice. Minister of Works, Dave Umahi, recently emphasised these points, sternly reprimanding dissatisfied foreign contractors. He urged them to stop undermining the implementation of concrete road technology in Nigeria. Umahi, who disclosed that he had obtained President Bola Tinubu’s approval to proceed with this transformative policy, made it clear that the government’s initiative to adopt concrete road technology would continue without hindrance during his tenure. Although the minister refrained from naming specific wrongdoers, he expressed his determination to crack down on contractors who manipulate asphalt thickness, denying the government and the people the full value of their investment.
According to a recent statement by the Infrastructure Concession Regulatory Commission (ICRC), about 135,000 kilometres of road network in the country are un-tarred. Nigeria has about 195,000 km road network out of which a proportion of about 32,000 km are federal roads while 31,000km are state roads. Out of this, only about 60,000km are paved. Of the paved roads, a large proportion is in very poor unacceptable condition due to insufficient investment and lack of adequate maintenance.
In last 24 years, the federal government has allocated substantial funds for road construction, totalling over N2.4 trillion in the last 24 years. Notably, N301.8 billion was earmarked for road construction in 2016, followed by N347.5 billion in 2017, N159.5 billion in 2018, N262 billion in 2019, and N315.5 billion in 2020 for works and housing. Additionally, N241.864 billion was allocated in 2021, N280 billion in 2022 for road infrastructure, and N356 billion for both works and housing in 2023, with N321 billion designated for capital projects.
However, mounting debt overhang for road contracts is a growing concern. The present administration currently owes contractors approximately N14 trillion for 2,604 roads covering 18,000 kilometers, inherited from the previous administration. There are apprehensions that the budget for road infrastructure might double due to these financial obligations. Umahi revealed, “The ministry has paid N4 trillion out of the N14 trillion owed to contractors between when we came on board and now. The balance left now is N10 trillion.”
This financial strain might be the driving force behind the pivotal policy shift of the Tinubu administration, transitioning from traditional asphaltic, coal tar, or macadamised roads to concrete pavement, especially for arterial roads. Umahi, a two-term governor of Ebonyi State and a civil engineer himself, played a pivotal role in this decision. He has successfully implemented concrete roads in his state, roads that have withstood the test of time.
Globally, transportation is acknowledged as a significant economic enabler, connecting goods and services to consumers across various societal segments. Nations worldwide consistently invest heavily in creating robust road networks. Road construction is a vital facet of infrastructural development, and the choice of materials for road pavements profoundly influences their durability, maintenance requirements, and overall performance. This decision-making process carries substantial implications for the nation’s road infrastructure and the convenience of its citizens.
Concrete and asphalt roads – any difference?
Concrete roads and asphalt roads differ fundamentally in their composition and properties. Concrete roads are constructed using a blend of cement, water, aggregates and sometimes chemicals to enhance adhesiveness, strength, and durability. Cement primarily binds the components together in concrete roads. Asphalt roads, on the other hand, utilise bitumen, a thick black liquid substance derived from petroleum, mixed with aggregates to create asphalt concrete. Asphalt roads have waterproofing properties, making them suitable for various weather conditions.
While concrete roads are generally considered more expensive upfront compared to asphalt, they offer lower maintenance costs and an extended lifespan, often lasting for at least 50 years. In contrast, asphalt roads start showing signs of wear and stress after around 15 years. Experts speculate that Umahi may have considered the long-term cost-effectiveness of concrete roads, which involve minimal maintenance expenses over their lifetime. Dr. Omolola Adetona, former Lagos State Chairman of the Nigerian Institution of Civil Engineers, acknowledges that the maintenance costs for rigid pavement, such as concrete roads, might be higher and more technical than those for asphalt. However, she notes that evolving technologies, particularly precast methods, could simplify the deployment of concrete pavements, reducing the need for extensive on-site preparations. Despite technical advancements, Adetona points out potential challenges, such as material scarcity due to widespread adoption and geometric inflation of resources like cement, sand, reinforcements, and labour.
Ogbonnaya Obasi, a veteran in the construction industry, finds the ongoing conversation about concrete roads intriguing. He suggests that Umahi is confronting the practical realities of road construction, particularly in areas where the soil texture favours the use of concrete pavements for specific arterial roads over flexible alternatives. This highlights the importance of choosing the appropriate road construction method based on local conditions and long-term sustainability.
While some, such as Isa Egbeyemi, attribute asphalt road failures to what he terms “the Nigerian factor,” emphasising the importance of precision in engineering, others argue for a combination of materials. Afolabi Adedeji suggests that arterial roads should be made of concrete due to their durability and the heavy loads they endure daily. However, he acknowledges the quick deployment advantage of asphalt roads, especially in rural areas. Concrete roads tend to last 40 to 50 years with minimal maintenance, making them a cost-effective choice in the long run.
Yet, the shift to concrete roads poses challenges. The initial cost for concrete roads can be significantly higher than that of asphalt roads. Adewuyi Adedeji, an engineer, highlights the cost difference: a kilometer of concrete road can cost up to N59,181,594.70, while an asphalt road costs around N49,766,822.68. This financial disparity raises concerns about job losses for local contractors, especially if multinational companies dominate the concrete road projects. Additionally, scarcity of bitumen, a key ingredient in asphalt pavements, could hamper the industry, necessitating government emphasis on bitumen exploration. The Cement Producers Association of Nigeria warns that the government’s concrete road plan might escalate cement prices. To mitigate potential crises, experts emphasise comprehensive soil tests to address soil challenges and suggest concurrent use of concrete and asphalt technologies, allowing time for contractors to adapt. Moreover, the government could support contractors by establishing machinery zones in each geopolitical zone, reducing equipment rental costs for road projects.
A recent report by Proshare Nigeria Limited, titled “Roads – Concrete Vision, Asphalt Competition: Looking Ahead,” also emphasised the crucial need for durable materials in road construction in Nigeria. The report highlighted that the primary challenge in road construction within the country has been poor durability, not inflated costs. Concrete roads were identified as having an advantage over asphalt-bitumen-based constructions due to their superior durability. According to the report, asphalt roads tend to deteriorate under heavy traffic and intense tropical weather, making them fragile and requiring frequent repairs. In contrast, concrete roads are significantly more durable, lasting between 25 and 30 years without major reconstruction or repairs. The report emphasised that, from a socio-economic cost-benefit perspective, concrete roads provide superior returns on social capital outlays in the medium to long term.
The report acknowledged the need for both concrete and asphalt roads, tailored for different parts of the country and various traffic conditions. It suggested constructing roads with heavy traffic and deadweight tension using concrete, while roads with lighter traffic and fewer vehicles should be built with asphalt technology, provided proper substructure preparation is undertaken. Regarding specific regions, the report recommended that roads in the southern part of the country, exposed to heavy rainfall and constructed on marshy and waterlogged terrains, should be made with concrete material. It also noted that both asphalt and concrete roads have their places in the overall infrastructure plan, with concrete being the default option for national and state highways, especially in regions experiencing heavy annual rainfall. Asphalt roads, on the other hand, are suitable for the northern part of the country with savannah plains and lower annual rainfall.
The report emphasised that commercial competitiveness should guide the road architecture aligned with Nigeria’s socioeconomic aspirations. It highlighted that efficient road networks are critical for facilitating the movement of goods and people, which, in turn, enhances the country’s economic competitiveness. The report stressed that improving transportation efficiency within Nigeria’s borders and expanding value distribution to neighbouring African states are essential steps, especially in the context of the African Continental Free Trade Area (AfCFTA).
In summary, evidence shows that concrete roads are highly durable and can last for several decades without significant wear and tear, especially when properly constructed; concrete roads require minimal maintenance compared to asphalt roads because they are less prone to potholes and cracks, reducing the need for frequent repairs; concrete roads can withstand heavy loads, making them suitable for high-traffic areas and industrial zones; concrete surfaces offer lower rolling resistance, potentially resulting in better fuel efficiency for vehicles. However, constructing concrete roads often involves higher initial costs compared to asphalt roads; concrete roads require adequate time to cure and harden before they can be opened to traffic, causing potential delays; the production of cement, a key component of concrete, contributes to carbon emissions, making it less environmentally friendly.
On the other hand, asphalt roads are generally cheaper to construct than concrete roads, making them a preferred choice for many projects; asphalt roads can be laid quickly and are ready for use shortly after construction, reducing traffic disruptions; asphalt is more flexible than concrete, allowing it to expand and contract with temperature variations, reducing the likelihood of cracks; damaged asphalt roads can be repaired relatively easily, and routine maintenance is simpler compared to concrete roads. However, asphalt roads have a shorter lifespan compared to concrete roads and may require more frequent resurfacing and repairs; due to wear and tear, asphalt roads need regular maintenance, including filling potholes and resurfacing, which can be costly over time; asphalt production involves the use of fossil fuels and can release pollutants into the environment.
Roads are the lifelines of a nation, connecting people, places and opportunities. The choice between concrete and asphalt, the two most common road construction materials, involves a careful consideration of various factors. In the Nigerian context, the debate often centres on balancing the immediate cost concerns with long-term durability and maintenance requirements. Factors such as the availability of funds, the expected traffic volume, and the local climate influence the decision-making process. Some regions might opt for concrete roads in areas with heavy industrial traffic, while others might choose asphalt roads for their cost efficiency and quicker installation. Ultimately, the choice between concrete and asphalt road construction in Nigeria requires careful consideration of all these factors to ensure the construction of reliable, cost-effective, and environmentally sustainable road networks.
