Wednesday, October 20, 2021

Mass Housing With NBRRI Stabilized Earth Blocks

Makava Richard
Makava Richard

Housing gives man a sense of mental security, protection from adverse weather conditions and other intending dangers, it boosts social well-being and helps promote self-esteem which in turn makes him comfortable and proactive to achieve other needs and set goals in life. A nation progresses when its citizens are provided with affordable housing as most of the labour force become more productive when they are adequately housed thus boosting the labour output and general development of the nation.

It is against this background that we must recognize the importance of the construction industry in the socio-economic development of a nation. Many a times, the national progress, technological and political advancement of most countries are reflected by the pedigree of their construction industry and the feats achieved over time.  The Nigerian building and construction sector should be no exception and it has been described by Okigbo (1982) and Mogbo (2001) as being ‘important’ and ‘crucial’ to her economy. Building materials were identified by Abiola (2000) as one of the principal factors affecting the performance of the building construction sector. With an estimated population growth rate of about 2.5 per cent, it is believed that 1.5 million new homes would be required annually between 2012 and 2025 (Hogarth et al, 2015). The magnitude of the housing deficit in Nigeria is such that government alone cannot cope with its mitigation. As a result, public-private partnerships are gaining ground as an important route for dealing with the housing deficit in the country. (Ibem and Aduwo, 2012).

NBRRI And Its Role In Tackling Housing Deficit 

Right from inception, the Nigerian Building and Road Research Institute has placed a priority on the development of alternative building materials which are locally available and the compressed stabilized earth blocks (CSEBs) is one of such innovations. The use of earth construction materials, techniques, and equipment are environmentally friendly and provide both comfort and affordability. This CSEB is a primary product from the natural clay in our environment referred to as laterite.

Clay is the oldest natural building material. It consists of a mixture of clay, sand, and dust. It may also contain coarser particles (gravel) or organic material. The most common way to use clay for construction is in the form of clay bricks or in the form of ramming. In addition, it presents the filling of half-timbered construction and wood framed construction or as a clay plaster.

Compressed Stabilised Earth Blocks

Compressed stabilised earth blocks (CSEB) are basically made from local materials (laterite) which is readily available in various parts of the country. The blocks are interlocking blocks and do not require plaster, paint and cement mortar in bonding the blocks during construction, thereby reducing building cost.

The use of CSEBs as a walling material is a sustainable construction technique as it is affordable, durable and accessible. When compared with alternatives such as fired brick and sandcrete blocks, CSEBs offer lower construction costs at comparable quality, and is suitable for a wide range of environments, and dramatically reduces the impact on the environment.

Other advantages are that it ensures the use of locally available construction materials thereby reducing transportation costs; ensures the availability of quality and affordable housing for a wider population; creates job opportunities as the technology requires semi-skilled labour which are easily transferable to locals; it generates local revenue as the materials and labour are sourced locally; and it is more energy efficient considering its lower embodied energy. CSEBs have very good insulation and thermal properties and also possesses the ability to absorb atmospheric moisture resulting in a healthier environment for the occupants.

Based on the cost analysis carried out by NBRRI on the blocks, it was found that NBRRI compressed stabilised blocks are cheaper alternatives to sandcrete blocks, giving a 20 per cent reduction in the total building cost. From the bill of quantities computed and using CSEBs in the construction of 1, 2 and 3 bedrooms, a percentage cost reduction of 22 per cent, 20 per cent and 21 per cent were obtained respectively compared to sandcrete blocks. These are interlocking walling units made from 90 per cent earth (laterite) and 10 per cent cement and water. The   blocks are dry-stacked, with each block interlocking into adjacent blocks to create strong   monolithic wall. The blocks are also laid to finish with a pleasant rustic-red colour of earth, obviating the need for plastering or painting.

Benefits of NBRRI CSEB

* Clay which is the main constituents are locally and abundantly available

* Less use of cement which is an expensive material for building

* Blocks are dry-stacked, interlocking into each, into a monolithic structure

* Ease of use with little or no supervision

* Ability for on-site production, curing and usage 

Application of NBRRI Technology

The CSEBs have been deployed in all the six geo- political zones of the country as constituency projects. Examples are skills acquisition centres, classrooms, assembly halls, healthcare centres, etc.  A comparative analysis was made for the walling materials in a 2-bedroom and 3-bedroom buildings respectively. A huge percentage difference was recorded.

Summary

Three-bedroom conventional NBRRI technology

 (1). Internal and external walls 1,225,000.00 979,650.00. 

(2) Finishes 536,700.00. Total 1, 761700 979,650 percentage difference 44.3 per cent.

Two-bedroom Conventional NBRRI Technology

(1). Internal and external walls 1,155,000.00 882,000.00. 

(2) Finishes 566,300.00. Total 1,721300 882,000 percentage difference 48.7 per cent.

It is to note that these blocks are compressed with a force of 5N/mm² using hydraulic or manually operated machines. This makes them dense and suitable as external and internal walling material.

NBRRI Compact Interlocking Block Making Machine

     i.   Features:

·      Dimension (1100*600*1500) mm

·      Retractable tricycle suspension system

·      A 6.5hp water cooled diesel engine

·      Speed of 2800 rpm

·      1500 blocks / day

·      Portable

   ii.   Significance/Benefits:              

·      Reduction of machine production cost by trimming-off excess capacities/components

·      Reduction of operational production cost by adopting lower fuel and oil utilizing       mechanical systems

·      Ensuring machine portability with minimal manual ease and at a comparative lower cost

·      Reduction of production down time by utilizing locally available serviceable standard

 parts

·      Reduction of production cycle by fully automating the actuation mechanisms

·      Adopting tropical weather friendly systems

·      Closing the overall national CSEB’s production demand gap

·      Creation of a value chain in the utilization of local raw materials and methods

·      Promotion of inventions and innovations in the institute’s STI policy

·      Fast tracking the commercialization of the institute’s interlocking blocks walling technology through prototyping

·      Enhancing PPP strategy in building sub-sector of the construction industry.

iii.            Application:           

● Small and medium scale housing production        

● PPP projects

● Energy demand reduction-based projects

 ● Remote sites

Conclusions/Recommendations

In line with this, it is imperative to recognize the fact that the cost reduces when it is to be deployed in multitudes.

1. Restructure and adequately fund the Nigerian Building and Road Research Institute (NBRRI) to perform its statutory role.

2. Grant’s fiscal incentives to small and medium scale local manufacturers of locally sourced building materials. 

3. Reduce the dependency on imported construction materials and technologies. 

4. Encourage the use of laterite/clay (CSEB) as a walling for mass housing employment and wealth generation. 

5. The use of CSBs in mass housing delivery programmes can be promoted through effective public enlightenment programmes targeted at all stakeholders.

Makava Richard is the special assistant on social media to the director-general of NBRRI, Prof. Samson Dun. He can be reached on makrichprince@gmail.com.

Makava Richard
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