NUI Galway – UL Alliance First Annual ENGINEERING AND - ARAN ...

Cost-Effective Sustainable Construction Technology.
Declan Gavigan 1 & Jamie Goggins 2
National University of Ireland, Galway, Ireland.
1) D.Gavigan1@nuigalway.ie, 2) Jamie.Goggins@nuigalway.ie
Abstract
Through this research project, the development of a
novel cost-effective sustainable composite building
technology or product for use in a European context
will be proven through extensive testing in terms of
durability, strength and appearance. In particular,
composite materials comprising of locally sourced
materials that have low impact on the environment are
being developed. One construction technology used in
developing countries that has very low impact on the
environment is stabilised soil blocks (SSBs). The blocks
are low-cost as their main component, the soil, is
sourced locally, often directly from the site of
construction and the main stabiliser used in their
manufacture is cement. Further, these blocks can be
produced on site, saving in transportation costs.
This research project is separated into two phases;
the first phase investigates alternative binders and
stabilisers to Ordinary Portland Cement (OPC), which
have pozzolanic properties and are mainly waste
materials or by-products of no significant value. The
second phase of the project aims at producing
innovative composite materials by developing the use of
these alternative waste materials as stabilisers in SSBs
and investigating the use of these SSBs in a European
context.
1. Introduction
Concrete is the most utilised substance in the world
after water. Ordinary Portland Cement (OPC), the most
common binder used in concrete, is the most expensive
and energy intensive ingredient in concrete. Due to the
manufacturing process associated with cement
production, approximately 900kg of CO2 is released
into the atmosphere for every tonne of cement
produced. Therefore, it is imperative that alternative
cement replacements are developed. Consequently, the
quantity of cement being manufactured would be
radically reduced. Wide-spread research has been
carried out in the development of cement substitutions.
Ground granulated blasfurnace slag (GGBS), and fly
ash are commonly used in blended cements or as
cement replacements across Europe.
2. Investigation into alternative binders
A full review of various Ordinary Portland Cement
(OPC) replacement materials has been investigated. A
wide range of agricultural and industrial waste products
are examined in terms of their physical and chemical
properties and their suitability as a cementing material
in an attempt to convert waste products into useful
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construction materials. It has been revealed that the use
of these materials in concrete or soil blocks not only
reduce their cost and embodied energy, but also
improve their structural performance. It is obvious that
different substitution materials will have different
effects on the properties of concrete due to their
chemical and physical characteristics, so it is vital that
these characteristics are considered and analysed
thoroughly.
3. Concrete Block Testing
Concrete containing both 10% and 20% of the
various waste materials was tested in terms of
workability, permeability, shrinkage, durability and
strength at 3, 7, 1, 28, 56 and 90 days. The various tests
were carried out on 100x100mm cubes and 150 dia.
x300mm cylinders. Durability tests included the
concretes resistance to sulphate attack and chloride
ingress. From these test results, the most successful
replacement was determined in terms of strength and
durability with respect to concrete.
4. Stabilised Soil Block Testing
In terms of masonry blocks, compressive strength
isn’t the most critical characteristic. Assuming the soil
is adequately compressed and suitable soil is used in the
making of the blocks, avoiding the use of topsoil with
high levels of organic matter, the target strength should
be met. Durability is the main concern with SSBs. The
ability of the soil in the blocks to resist prevailing rain,
wetting and drying cycles, freezing and thawing cycles,
and chemical attack are critical issues if there are
applicable in a European climate. The testing of the
SSBs, incorporating the waste material as a stabilizer,
will mainly focus on durability tests. The most common
method used in the manufacturing of SSBs is a hand
press for compacting the blocks. A more efficient
method, which will be considered as part of this project,
is to use an electric or diesel powered machine that
have high production rates.
5. Conclusions
Through this research project the successful use of
SSBs, incorporating a waste material sourced in Ireland
as a stabilizer instead of cement, in a European context
will be proven.
6. Acknowledgements
The first author would like to thank the Irish
Research Council for Science, Engineering and
Technology (IRCSET) EMBARK Funding Initiative,
who are funding this research project.