the influence of mineralogy and particle size on mud house...
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The Influence of The Influence of Mineralogy and Particle Mineralogy and Particle
Size on Mud House Size on Mud House Construction in Rural Construction in Rural
BangladeshBangladesh
D J C LamingD J C LamingHerrington Geoscience and Housing and Hazards Group (UK)Herrington Geoscience and Housing and Hazards Group (UK)
R L P HodgsonR L P HodgsonUniversity of Exeter and Housing and Hazards Group (UK)University of Exeter and Housing and Hazards Group (UK)
M J HeathM J HeathSheffield Hallam University and Housing and Hazards Group Sheffield Hallam University and Housing and Hazards Group
(UK(UK)
The challengeThe challenge
Some 90m Bangladeshis Some 90m Bangladeshis live in rural nonlive in rural nonengineered houses that engineered houses that provide inadequate provide inadequate protection against natural protection against natural hazards.hazards.
Housing & Hazards is a Housing & Hazards is a network of professionals network of professionals dedicated to developing dedicated to developing improved technologies for improved technologies for use in rural Bangladeshuse in rural Bangladesh
Diversity in House ConstructionDiversity in House Construction
Traditional house types, Traditional house types, from fragile bamboo and from fragile bamboo and straw shelters to substantial straw shelters to substantial mud structures, appear to mud structures, appear to occur at random on the occur at random on the alluvial plains of alluvial plains of Bangladesh. Bangladesh.
Variations in construction Variations in construction method commonly reflect method commonly reflect the local availability of the local availability of construction materials and construction materials and their characteristics, their characteristics, including the geological including the geological materials present materials present
Materials usedMaterials used
The results of a survey of wall The results of a survey of wall construction materials made construction materials made in N Bengal, 1997. This is in N Bengal, 1997. This is fairly typical of national fairly typical of national statistics. statistics.
Local variations can occur. A Local variations can occur. A recent survey in a sandy riverrecent survey in a sandy riverbank area found that 95% of bank area found that 95% of houses were of woven houses were of woven bamboo because the muds bamboo because the muds there were not sufficiently there were not sufficiently cohesive.cohesive.
Carter M L (1997). Rural housing and affordable innovation, Housing & Hazards Monograph No 1, 101pp
Layered mud 51%
Bamboo + Mud 30%
Woven Bamboo, 11%
Brick, 4%Other, 4%
A high proportion of Bangladesh's rural homes are A high proportion of Bangladesh's rural homes are composed partly or entirely of mud, which collapse composed partly or entirely of mud, which collapse readily when flooded.readily when flooded.
One focus of H&H's One focus of H&H's research has been to research has been to investigate better ways of investigate better ways of using and stabilising mud.using and stabilising mud.
This paper relates soil typeThis paper relates soil typeto options for cement to options for cement stabilisation.stabilisation.
Focusing on mud buildingFocusing on mud building
Distribution of Soil TypesDistribution of Soil Types
Brammer (1996) Brammer (1996) identified 23 physioidentified 23 physiographic regions in graphic regions in Bangladesh and the Bangladesh and the associated soils. associated soils.
Broadly, soils grade from Broadly, soils grade from light sandy silty in north light sandy silty in north to heavy clays bordering to heavy clays bordering Bay of BengalBay of Bengal
Brammer H (1996). The geography of the soils of Bangladesh. University Press Ltd, Dhaka, 287pp.
Field studies made at three Field studies made at three locations in Dinajpur locations in Dinajpur (sandy), Manikganj (sandy), Manikganj (silt/clay), & Gopalganj (silt/clay), & Gopalganj (peaty).(peaty).
Paper reports findings in Paper reports findings in terms of local soil types terms of local soil types and in relation to the and in relation to the national soil distributions national soil distributions
Study locationsStudy locations
Community ParticipationCommunity Participation
Studies used ActionStudies used ActionResearch to engage Research to engage communities in housing communities in housing improvements.improvements.
Participants shared Participants shared experiences of the experiences of the building process and building process and developed appropriate developed appropriate improvements.improvements.
Village construction workshop, Dinajpur District
Cementstabilised MudCementstabilised Mud
Practical and laboratory Practical and laboratory experiments showed that experiments showed that OP Cement can be used OP Cement can be used economically to make economically to make building mud resistant to building mud resistant to flooding. flooding.
Different pozzolans were Different pozzolans were tried but only OPC gave tried but only OPC gave water resistance at an water resistance at an economic cost economic cost
OPC-mud blocks after 3 months inundation at BUET
It may be formed into blocks It may be formed into blocks to construct walls to construct walls
Or used in place of Or used in place of traditional solidmud building traditional solidmud building materials.materials.
Building with CementMudBuilding with CementMud
Building first stabilised mud house, Dinajpur 2002
A simple soil testA simple soil test
The success of cement The success of cement stabilisation process is stabilisation process is governed by the clay content governed by the clay content of the soil. of the soil.
Too much clay and the result Too much clay and the result is badly mixed and weak.is badly mixed and weak.
A simple sedimentation test A simple sedimentation test can be made in the field, as can be made in the field, as shown here.shown here.
Location Sand/Silt%
Clay%
Stabilisation process
Dinajpur >80 <20 35% cement
Manikganj >60 <40 5% cement
Gopalganj <20 >80 89% cement + 20% sand
How much cement?How much cement?
Soil properties and cement stabilisation details for each of the study sites
NOTE that Gopalganj is in an area of organic soils
Based on this, the Based on this, the Brammer soil map Brammer soil map suggests that floodsuggests that floodresistant cementreinforced resistant cementreinforced mud houses could be built mud houses could be built in about half of in about half of Bangladesh’s lowlying Bangladesh’s lowlying rural areas, although more rural areas, although more detailed fieldwork is needed detailed fieldwork is needed to identify the most suitable to identify the most suitable soils in each localitysoils in each locality
Extending this experienceExtending this experience
Other relevant soil propertiesOther relevant soil propertiesMineralogy and organic content also importantMineralogy and organic content also important
Swelling minerals (montmorillonite) may occur in Swelling minerals (montmorillonite) may occur in the lower Meghna/Padma delta.the lower Meghna/Padma delta.
Lime is available in some areas.Lime is available in some areas.
This presentation is the This presentation is the start of wider investigation start of wider investigation into options for improving into options for improving mud construction in mud construction in BangladeshBangladesh
Changing PracticeChanging Practice
Ranges of soil types will be found in any given Ranges of soil types will be found in any given area due to variations in depositional environment.area due to variations in depositional environment.
Experienced mud builders will choose the most Experienced mud builders will choose the most cohesive soils available. In sandy areas builders cohesive soils available. In sandy areas builders may not consider mud building at all.may not consider mud building at all.
Changing traditional practice is A CHALLENGEChanging traditional practice is A CHALLENGE
This group remains adamant This group remains adamant that they cannot build mudthat they cannot build mudhouses with their sandy soilshouses with their sandy soils
Barriers to new techniquesBarriers to new techniques
There are also socioeconomic barriers to lowcost There are also socioeconomic barriers to lowcost home improvement.home improvement.
Home owners aspire Home owners aspire to modern materials.to modern materials.
Some cannot afford Some cannot afford any extra cost.any extra cost.
Women have little Women have little influence over 'men's work'influence over 'men's work'
Other H&H studiesOther H&H studies
Housing & Hazards' links have Housing & Hazards' links have also conducted experimental also conducted experimental research into wind effects on research into wind effects on small buildings and into small buildings and into appropriate ways of appropriate ways of disseminating technical disseminating technical information.information.
Wind tunnel tests in Exeter
Mud mixing training, Dinajpur
ConclusionsConclusions
Soil data from the study sites demonstrate the Soil data from the study sites demonstrate the importance of soil characteristics in understanding importance of soil characteristics in understanding present practice, and in developing novel present practice, and in developing novel technologies with the aim of providing hazardtechnologies with the aim of providing hazardresistant homes in many parts of rural Bangladeshresistant homes in many parts of rural Bangladesh
The study data can be extended nationally using The study data can be extended nationally using published soil informationpublished soil information
Work is still needed to confirm local conditions and Work is still needed to confirm local conditions and to address attitudes and socioeconomic barriers to to address attitudes and socioeconomic barriers to development.development.