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
Compressive strength is not an issue with rammed earth blocks. Weaker hand moulded blocks reach strengths of 2-4 N/mm 2 Durability is an issue. Stabilisation with cement or lime will significantly improve durability
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% cement 1:12 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
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
MONARFLE X Failure REFLEX Failure DIFFERENCE Plastic sheeting ‘WARP’ 275N451N+176N Plastic sheeting ‘WEFT’ 259N480N+221N Reinforced sheeting band 1335N1241N+94N Single nail fixing 39.6N231N+191.4N Single nail with small plastic washer fixing 115.8N231N+115.2N Single nail with 25mm large washer fixing 234N279N+45N Single nail with rope washer 140N250N+110N Large plastic eyelet fixing 165N307N+142N Brass eyelet 92N217125N Test Results table
The results indicated that Reflex is considerably stronger than the older form Monarflex plastic sheet. The most effective fixings were the large 25mm steel washer and the large plastic eyelet. However, a 50mm round stone wrapped in plastic sheet and tied round with guy rope proved to be the 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.
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.