The cost and environmental benefits of the utilisation of soil in infrastructure development far outweighs those of hauled stone or concrete. Soils have relatively low load bearing capacities and often require stabilisation.
For use in buildings higher strength
thresholds necessitate intensive firing of clay soils into bricks. This
is expensive and environmentally undesirable. Avoiding firing requires
use of materials such as lime and/or Portland cement (PC), whose
manufacture depletes global energy resources and exacerbates atmospheric
The situation is exacerbated in low or
middle-income countries (LMICs), where affordability is a major
obstacle, as many do not manufacture Portland cement locally.
combining environmental as well as cost considerations, researchers at
AMTeC have made significant impact by aiming to address the realisation
of the UN Sustainable Development Goals (SDGs) by way of sustainable
unfired clay material systems.
The aim is to utilise marginal, waste and by-product materials from nature, industry or from agricultural activities. In this endeavour, some formulations have been very successful as to obviate the need to use Portland cement at all.
one such case, we have developed a novel cement that utilises ground
slag, a by-product from the manufacture of steel. This novel eco-cement
was trialled in the soil stabilisation for the A420 Tingewick Bypass in
Buckinghamshire. This was very successful, and besides high strength,
the cement was able to suppress sulphate-induced swelling that has
traditionally challenged civil engineers and has caused major road
failures worldwide, including on the M40. The M40 failed within 2 year
of initial construction because of this problem.
The team’s publications on swelling of sulphate-bearing soils became very popular and have many citations. Other roads in UK, including the A130 near London, adopted the lime-slag technology.
From the pioneering work on lime-slag formulations, other industrial waste materials were trialled with great success. In another successful novel cement, utilisation wastepaper sludge ash was so successful because of combining two waste streams in a synergistic manner. This warranted consideration of a patent, and the technology is encapsulated in a USW-Registered Patent No. PCT/GB2002/000708.
The reputation from the performance on strength and volume stability of slag-based novel cements was phenomenal and did not escape notice in UK Industry.
Prof John Kinuthia was a national awardee of the prestigious Royal Society Brian Mercer Award for Innovation on unfired scaly systems. This was a national award, and it boosted research in team’s morale to greater heights.
proceeds from the RS award transformed testing of souls at AMTeC, from
use of analogue proving rings and dial gauges to load transducers and
Linear Variable Displacement Transformers (LVDTs) for swelling
Support and recognition continued to increase
via additional UK and Welsh Government funding (from Royal Academy of
Engineering (RAE), Collaborative Industrial Programme (CIRP), Knowledge
Exploitation Funding (KEF), Academia for Business (A4B), Knowledge
Education Economy Skills Scholarships (KESS) and ScoRE CYMRU), all for
the development of eco-(unfired) materials.
From this robust
background, recognition was meteoric and culminated with that by the UN
UNESCO Committee. UNESCO provided global recognition, by supporting
scoping of eco-materials in Africa, with case studies in Kenya and
Cameroon. In Cameroon for example, the UNESCO-funded research work
enabled policy changes on the use of unfired bricks.
Researchers at AMTeC assisted in the development of Cameroonian standards on bricks (MIPROSPECS) by working with a local materials promotion authority - Mission de Promotion des Materiaux Locaux (MIPROMALO).
project to inform the standards comprised of a housing estate for the
Baka forest tribe (sometimes referred to as Pygmies) at Bertou,
Cameroon. The tribe faces challenges of deforestation where forests have
traditionally provided shelter.
In Kenya, impact is ongoing,
where AMTeC staff are involved in a project dealing with interlocking
bricks, thus not requiring jointing mortar and hence making immense
A PhD researcher has completed a PhD on this in
Kenya in 2019 and in Zambia, impact involved curriculum development and
during tenure as extremal examiner/advisor during 2010-12.
Rwanda, AMTeC is currently informing ongoing work on low-cost housing
by multi-national NGOs - MASS Group, Greenpact Africa and Earth Enable.
holistic impact from this work reported here has led to invitations in
panels and grant evaluations activities at the global level.
Professor John Kinuthia