May_1970 — Page 29

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Soil-cement research in the Philippines

BARRIO and feeder roads, parking areas, play courts, sidewalks and hous- ing are all encompassed by a research study on soil stabilisation which has been initiated by the College of En- gineering of the Mindanao State Uni- versity in Marawi City, Philippines.

The major objectives of the re- search are to determine: 1. the most economical and most effective method of utilizing natural soil at or near con- struction sites for the development of low-cost secondary road systems and play courts; and 2. the feasibility of using stabilised natural soil as low-cost building block for self-help housing projects.

The long-range plan is to investigate soil-cement, soil-asphalt and mechani- cal stabilisation in order to determine both the most effective and most eco- nomical method. Initial emphasis is being placed on soil-cement mixtures to find the optimum cement content and moisture required for satisfactory characteristics.

Stabilising soil with Portland ce- ment entails thoroughly mixing Port- land cement and water with soil and compacting the mixture before hydra-

tion of the cement takes place. After the cement hydrates, the compacted layer becomes hard and strong and will not soften when exposed to water. Ths

KITCHEN

LIVING DINING

BED

BED

Soil-cement house floor plan. Floor area: 484 sq. ft.

use of Portland cement in quantities ranging from eight to 16 per cent by dry weight is the most widely used ratio of chemical additives for stabili- sation. On this basis, low-cost high- ways in the United States have a gener- ally satisfactory service record.

Soil-cement house

The Mindanao research programme consists of both laboratory and field phases. Representative soil samples are secured from MSU campus for analy- sis. They are taken from shallow test pits at depths of up to 12 inches.

The samples are then processed and prepared for determination of proper- ties such as natural density, grain size distribution, Atterberg limits, and density-moisture content-compaction energy relationships. Work to date shows that 14 per cent cement or a proportion of one part cement to ap- proximately 10%1⁄2 parts of loose soil is optimum for the majority of the MSU soils. An optimum moisture content ranging from 30 to 32 per cent has been observed.

The objectives of the field soil- cement experimental sections are: 1. to observe and evaluate the perform- ance of a 4in. thick sidewalk, 9in. and 6in. thick roadway sections, and 4in. thick play court areas under vehicular and pedestrian traffic.; 2. to compare the performance of field experimental sections with the performance of laboratory specimens which were pre- pared from a representative cross-

Far East BUILDER, May 1970

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