SINGAPORE & THE FEDERATION OF MALAYA
To ensure uniform conditions in the testing of aggregates, preparation of trial mixes and crushing con- crete cubes the whole of the Concrete Laboratory is main- tained under constant conditions of temperature and humidity throughout the year. An air temperature of 64°F is adopted as the standard.
After commencement on the project, if it is justified in scope, laboratory work is continued on the site through- out the duration of the job. Samples of aggregates are frequently taken and checked to ensure that their grading and cleanliness comply with the specification. Frequent daily checks are made on the water content of aggregates and the amount of water added to the concrete mixer is adjusted accordingly. Test cubes are prepared and stored until they are at the correct age for crushing.
By the use of these methods considerable savings in cement may be made. Common defects in concrete such as honeycombing, shrinkage cracks, "blowing" and con- struction joint weakness may be avoided by adopting correctly proportioned and graded aggregates of the required standards of quality.
The concrete section is also concerned with other research matters such as concreting technique in tropical climates, special types of cast in-situ concrete for low cost housing, investigations into attack by sulphates and problems of alkali-aggregate reactivity.
Building Materials.
The work of this section covers a very wide and diverse field. Bricks are tested for strength and other properties including the use of bricks for refractory and other special purposes.
Paints and putties are tested for quality and their suitability for covering various types of surface and resistance to tropical climates. Materials for plaster are investigated in connection with cracking and crazing or where chemical reaction with the backing material is suspected as the cause of failure. Soils are analysed to determine whether any substances such as gypsum, which
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attack foundation concrete, are present. Miscellaneous defects in buildings, such as the cracking and expansion of concrete in chimney flues, splitting of joinery work, deterioration of wall boards, corrosion of metals, staining of concrete and masonry, etc. are investigated and the causes traced by scientific methods.
New techniques in building construction such as pre- fabrication, lightweight blocks, use of substitute materials, mechanical handling plant and mass production methods are investigated and developed.
Asphalt and Tarmacadam.
The need for laboratory control of asphalt and tarmacadam production has been realised for a long time by road engineers. Road surfacing will not withstand the abrasive action of heavy traffic unless the aggregates are closely and correctly graded and the appropriate type of bitumen or tar used as the binder material. The type of asphalt carpet is varied to suit the thickness of the carpet and the nature of the base course layer, the density of traffic and type of stone which is locally available.
The asphalt section of the laboratory is mainly con- cerned with investigating and testing aggregates, bitumen and tar for surfacing work and flat roof construction. It also maintains site laboratories at production plants for quality control in the field. Research work is carried on continuously on new types of mastic asphalt for flat roofs and floors and developments in carpeting material.
The purpose of this article has been to show how scientific methods can aid the contractor to plan his con- struction programme with the knowledge that no unforeseen difficulties can arise in foundation excavation. He can select concrete aggregates to comply in the most economical way with the designer's requirements of strength and facilities are provided for full investigation of all local building materials from the point of view of quality and durability. By means of site laboratories a close technical control is made on production and workmanship through- out the progress of the job.
LONDON EDINBURGH
CAIRO
BAGHDAD
SINGAPORE
WIMPEY
(INCORPORATED IN ENGLAND)
ESTABLISHED 1880
CONTRACTORS FOR THE BANK OF CHINA BUILDING.
HONG KONG,
P. O. BOX 97
OR
61M. BUKIT TIMAH ROAD
SINGAPORE.
TELEPHONE 82211 3