Solent University

Research for Oxfam,

Sheltercentre and others

Background

Small practical undergraduate projects that have arisen from

questions posed at various sheltercentre meetings.

Rammed Earth Blocks

1. Produce a block that is cheaper and easier to produce than concrete blocks or fired bricks

2. A block that is environmentally sound and durable

3. Use of minimal stabilisation (lime or cement)

Objectives

Makiga ram

ISSB using a MAKIGA ram

Compressive strength is not an issue with rammed earth blocks.Weaker hand moulded blocks reach strengths of 2-4 N/mm2

Durability is an issue. Stabilisation with cement or lime will significantly improve durability

Hand made un-stabilised blocks in Eastern Chad

UK clay for manufacturing bricks was used. Consisting of 65% fine grained clay-like material with similar properties to lateritic tropical soils.

Stabilisation: 1:20 5% cement1:12 8% lime

These are minimal. Typical recommended figures suggest 12 – 18% in which case perhaps concrete blocks would be better?

Earth and stabilisation

1year of weathering in exposed UK location

LIME PLAIN CEMENT

6 years of weathering in UK

Rammed Lime Plain Cement

Flooring to Cold Climate Emergency Shelters

• No standards or best practice to date

• Research into cold climate tents, but…..

• Current flooring solutions proving inadequate

• Develop and trial a simple and easily replicable testing procedure

• Produce a comparative league table of material compositions for use in a cold climate emergency insulated floor

Frozen Ground

Sub-base Layer

Insulating Layer

= Layer of Plastic Sheet

Materials & Testing

10 Kg

• Waterproof bottom layer of plastic sheet

• Robust and thermally effective layer of material

• Layer of plastic sheet to separate materials

• Insulating layer

• Upper surface of plastic sheeting for living space

Results

Performance of Material Compositions

0

2

4

6

8

10

12

Stones andStraw

Sand and Straw Stones andThermafleece

Sand andThermafleece

Stones andReed Mat

Sand and ReedMat

Material

Tem

per

atu

re D

iffe

ren

ce (

°C)

SettledTemperatureDifference

Camping Mat

Single LayerPlastic Sheet

Fixings to Plastic SheetingFixings to Plastic Sheeting

Tensile testing

MONARFLEX Failure

REFLEX Failure

DIFFERENCE

Plastic sheeting ‘WARP’ 275N 451N +176NPlastic sheeting ‘WEFT’ 259N 480N +221NReinforced sheeting band 1335N 1241N +94NSingle nail fixing 39.6N 231N +191.4NSingle nail with small plastic washer fixing

115.8N 231N +115.2N

Single nail with 25mm large washer fixing

234N 279N +45N

Single nail with rope washer

140N 250N +110N

Large plastic eyelet fixing 165N 307N +142NBrass eyelet 92N 217 125N

Test Results table

The results indicated that Reflex is considerably The results indicated that Reflex is considerably stronger than the older form Monarflex plastic stronger than the older form Monarflex plastic sheet.sheet.

The most effective fixings were the large 25mm The most effective fixings were the large 25mm steel washer and the large plastic eyelet.steel washer and the large plastic eyelet.

However,However, a 50mm round stone a 50mm round stone wrapped in plastic sheet and tied wrapped in plastic sheet and tied round with guy roperound with guy rope proved to be the proved to be the strongest fixing!strongest fixing!

Reinforcing concrete with indigenous and waste

materials found in the field

Replacing mild steel reinforcement in concrete, with indigenous, waste materials in non-load bearing, non structural concrete structures, such as water tanks, water wells, lintels, latrine slabs etc.

Testing beams

0

1

2

3

4

5

6

7

8

9

Bambo

o Re-

bar

Fibre G

lass

- W

oven S

trand

s

Steel

Re-bar

Fibre G

lass

- Chop

ped

Strand

Bambo

o Stra

nds

Plastic

Stra

pping

Plastic

Bot

tles

Plastic

Bot

tle T

ops

50mm

Mon

o-fle

x Plas

tic

Steel

Wire

Woo

l

Plain

Concr

ete lin

tel

Coconut

Hus

k

Straw M

attin

g

Additive Material

Ten

sile

Lo

adin

g (

kN)

Tensile Strength

             

Weakest

Strongest

Durable Surface Finishes To Rammed Earth Blocks.

The testing involved two primary and measured stages with a third further research stage. The first stage was to complete a pilot test in order to establish the correct field adaptation of the “Geelong test” (New Zealand Standard NZS4297/NZS4298)

A – Test Bed.

B – Rammed Earth Block.

C – Drip Generator.

D – Water Hopper.

Engine oil and unfinished after

erosion.

Plain Lime Cement

Further details from gordon.browne@solent.ac.uk