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close this bookWater and Sanitation Technologies: A Trainer's Manual (Peace Corps, 1985)
close this folderSessions
View the documentSession 1 - Water and sanitation issues in third world countries
View the documentSession 2 - Introduction to the training program
Open this folder and view contentsSession 3 - Facilitation skills
Open this folder and view contentsSession 4 - Community mobilization
Open this folder and view contentsSession 5 - Math review
Open this folder and view contentsSession 6 - Concrete and reinforcement
Open this folder and view contentsSession 7 - Project documentation
View the documentSession 8 - Field demonstration: Formwork and pouring concrete
Open this folder and view contentsSession 9 - Introduction to environmental sanitation
View the documentSession 10 - Non-formal health education
Open this folder and view contentsSession 11 - Community water supply case study
Open this folder and view contentsSession 12 - Project planning and management
View the documentSession 13 - Community needs and resource assessment
Open this folder and view contentsSession 14 - Communicable diseases and control
Open this folder and view contentsSession 15 - Excreta disposal systems
View the documentSession 16 - Health education presentations
View the documentSession 17 - Basic drawing and blueprint reading
View the documentSession 18 - Field demonstration: block laying
View the documentSession 19 - Project planning: Latrine construction
View the documentSession 20 - Latrine construction
Open this folder and view contentsSession 21 - Women and water
Open this folder and view contentsSession 22 - Hydrology
View the documentSession 23 - Water supply improvements
View the documentSession 24 - Pumps: Installation, operation, maintenance
View the documentSession 25 - Field demonstration: Pump assembly and disassembly
Open this folder and view contentsSession 26 - Field demonstration: Pipework and plumbing
Open this folder and view contentsSession 27 - Principles of hand-dug shallow wells
View the documentSession 28 - Well site inspection and feasibility survey
View the documentSession 29 - Project planning: Well rehabilitation
View the documentSession 30 - Shallow well rehabilitation
Open this folder and view contentsSession 31 - Gravity water systems: Part I
Open this folder and view contentsSession 32 - Survey and measurement
View the documentSession 33 - Field demonstration: Surveying
Open this folder and view contentsSession 34 - Gravity water systems: Part II
Open this folder and view contentsSession 35 - Principles of spring development
View the documentSession 36 - Spring site feasibility survey and flow measurement
View the documentSession 37 - Project planning: Spring development
View the documentSession 38 - Spring development construction
View the documentSession 39 - Ferrocement technology and construction
View the documentSession 40 - Project planning: Ferrocement water tank
View the documentSession 41 - Ferrocement water tank construction
View the documentSession 42 - Constructing projects in a community
Open this folder and view contentsSession 43 - Proposal writing
View the documentSession 44 - Training review and assessment

Session 18 - Field demonstration: block laying

TOTAL TIME

Two Hours

OBJECTIVES

* Articulate the basic characteristics of three types of masonry bricks: adobe, soil/cement, and concrete


* Practice correct block laying, using appropriate mortar

RESOURCES

Attachment 6-A: "Concrete and Mortar"

PREPARED MATERIALS

Samples of brick making materials for the three brick types including soils, cement, and aggregates, an adequate supply of bricks for masonry, trowels, shovels, mortar boards, wheel barrows, builders' levels, line levels, and string

FACILITATORS

One or more trainers

Trainer Introduction

This session is designed to give the trainees hands-on experience laying blocks. It requires substantial preparation. Assemble the trainees (a group of no more than eight, preferably four to six) at the location of the demonstration.

Samples of brick making materials and tools should be laid out for observation. Also have ready-made bricks available to practice block laying. The bricks can be adobe, soil/cement, or concrete, whichever is most appropriate for local building conditions. The trainees will need to lay several courses of bricks, including corners, and an area should be prepared for that exercise. They should work in teams of two, one laying the blocks and the other supplying bricks and mortar. Make sure that the teams rotate the two roles. Trainees with experience in block laying should be divided among the groups. The resource material, Attachment 6-A, is meant to serve as reference information for the trainees.

PROCEDURES

Step 1

5 minutes


Present the objectives and format for the session.

Step 2

45 minutes


Lecturette on the characteristics of adobe, soil/cement, and concrete bricks.

Trainer Note

Discuss each type of brick thoroughly:

Adobe

Mention soil content. A sandy loam, sandy clay loam, or light clay loam soil type is best. The mixture should be 75% sand and 25% clay mixture, with no more than 15% pure clay. Water content is 15-20% mixed to a smooth mud like consistency. Simple soil tests may be performed to judge quality such as the agitating jar, ribbon extrusion, or drop-ball. Mortar can consist of the same materials as the bricks.

Soil/cement

Mention soil content; there should be no organic matter. Sandy soil is best. High clay content makes poor bricks. Cement content is normally between 6-12%. Water content is normally between 8-18%. Mortar can consist of the same materials as the bricks, or use a slightly higher cement content.

Concrete

Aggregate is normally fine and medium coarse sand, with fine gravel. A cement to aggregate ratio of 1:6 is adequate for most walls. Bricks for a water tank will need a higher-cement content. Mortar should consist of a cement and fine sand mixture, normally a 1:4 ratio.

For all three types, describe how the bricks are made, and the curing process. Also, mention their strengths, weaknesses, and primary application. A summary of these characteristics is as follows:

Adobe

Made manually in wooden forms. Sun-dried curing process.


Strengths:

Inexpensive, readily available, easy to make, ease of construction, good thermal properties


Weaknesses:

Low compression strength, low resistance to moisture and erosion, high maintenance requirements, hard to transport, irregular shape


Applications:

Low-cost housing, low cost latrine superstructure or pit lining

Soil/Cement

Made manually in wooden forms, block press, mechanically-pressed, or hydraulically-pressed. Open air curing process with water.


Strengths

Better compression strength if pressed, relatively inexpensive, ease of construction, requires more skill to make when pressed but high production capacity and regular shape


Weaknesses:

Relatively low resistance to moisture and erosion, medium maintenance requirements, hard to transport


Applications:

Low-cost housing, low cost latrine superstructure or pit lining

Concrete

Made manually in wooden forms or manufactured. Open-air curing process with frequent water applications


Strengths:

High compression strength, good resistance to moisture and erosion, easy to transport, regular shape, high production capacity if manufactured


Weaknesses:

Relatively expensive, may require high transportation cost


Applications:

Housing, latrine structure, water tanks, schools, clinics, etc.

Step 3

1 hour


Trainees practice block laying using appropriate mortar.

Trainer Note

Demonstrate the correct procedures. Make sure trainees are given ample time to practice mixing mortar and laying blocks on their own.

Step 4

10 minutes


Review the objectives and conclude the session.

REFERENCE: Ronald Stulz, Appropriate Building Materials, Swiss Center for Appropriate Technology and Intermediate Technology Publications. London, England.