No_4_1956 — Page 75

INTRODUCTION OF PREPAKT CONCRETE

DIRECTORS OF AJAX ENGINEERING & CONSTRUCTION CO.. LTD. Messrs. N. Hart-Baker, A. R. Sedgley, C. W. Beckwith, R. P. Brown and C. A. Peterson.

constituted that a secondary function is performed that of eliminating settle- ment, plugging, bleeding and setting shrinkage, all of which are pronounced when Portland cement mortar alone is used.

Alfesil separates the cement particles when first placed in the mix, and prevents the cement particles from clinging to- gether. The Alfesil possesses cementing properties, and during hydration combines with the lime released by the Portland Cement to form additional strength-pro- ducing compounds.

The Intrusion Aid increases the flow- ability and pumpability of the mortar and at the final setting stage acts as a slight expansion agent.

Since primarily the Prepakt Concrete system is concerned with the proper mix- ing and efficient placing of the grout and since the handling and preparation of this On Wednesday, 13th February

grout can be more efficiently controlled 1957. Briefly speaking, Prepakt Concrete is a the Directors of Ajax Engineering

and more flexibly applied than a con- & mass of properly graded coarse aggregate Construction Co. Ltd. hold а cocktail surrounded and held together by a har- Crete mixture in which the coarse aggregate party and

a fiim show to introduce the dened Prepakt mortar.

is incorporated, it would appear that the The mortar is idea of Prepakt Concrete into Hong Kong. composed of a properly designed mixture system has rather startling possibilities.

of Portland cement, Alfesil, sand and The Far East Representative for Pre-

Prepakt handbooks and pamphlets des- pakt Concrete Company

water to which is added an appropriate cribe a multitude of projects both of land of Cleveland, Ohio, U.S.A. Mr. John A. Cave was pre-

amount of Intrusion Aid. Prepakt Con- and sea work in which the Prepakt method sent

at this meeting and discussed with crete is manufactured by packing forms made possible the placing of concrete guests various uses of Prepakt Concrete tightly with coarse aggregate and pump under conditions which would normally and Prepakt Concrete Piles He also furnishing Prepakt mortar in the form of slurry be impossible by ordinary methods. ed the listed details on this concrete and into the coarse aggregate to fill the voids explained the film and slides that were between the particles and to consolidate shown.

the mass.

Mr. Cave who is at present residing in Japan will shortly take up residence in the colony.

The Ajax Engineering & Co.,

Construction

in

As far as Hong Kong is concerned, pro- bably the most interesting application of this system is in piling work, particularly in unstable soils, where driving vibrations endanger nearby installations headroom is limited.

crete

OT where

con-

Prepakt Concrete differs from ordinary concrete in the manner of manufacture, in the proportioning of aggregates, and in the cement requirements. In ordinary concrete, the coarse and the fine aggre- The Prepakt cast-in-place piles are made Ltd. was recently formed in Hong gates are mixed together with cement and by augering holes in foundation material Kong, the Directors being Mr. Charles A. water and the entire mass is then placed and filling the holes with Intrusion mortar Peterson, Mr. Clifford W. Beckwith and

in forms. Sufficient rich mortar must be or with coarse aggregate followed by con- Mr. Alos R. Sedgley, well-known Ameri-

Intrusion can engineers and business men, the local used to keep the heavy particles of coarse solidation with

mortar. The members of the Board being Mr. Robert aggregate suspension during mixing, resulting piles exhibit several features of Philip Brown, Mr. No man Hart-Baker, placing and setting.

important engineering value, namely:- with Mr. R. E. Moore as Legal Adviser.

In the making of Prepakt Concrete the

1. The engineer and owner are assured of At the first meeting of the Company heavy coarse aggregate particles are pack-

absolutely continuous shafts of held

on the 2nd February, 1957, Mr. ed tightly in the forms and do not require

without honeycomb, entrapped Charles A. Peterson was appointed Manag- an excess of mortar to keep them in sus-

water pockets, or segregation effects ing Director of the Company, Mr. Robert pension.

from end to end. A greater amount of solid ag Philip Brown was appointed Director of gregate particles is built into Prepakt 2. Operations, Mr. Clifford W. Beckwith was Concrete and smaller amounts of cement appointed Director of Administration. Mr. water paste are required. The close pack- Arlos R. Sedgley was appointed Director ing of the coarse aggregate particles, the of Engineering and Mr. Norman Hart-

reduction in cement requirements, and Baker was appointed Director of Works the addition of Prepakt Concrete materi- in charge of machinery plant and equip als (Alfesil and Intrusion Aid) practically

eliminates settling and setting shrinkage. The Ajax Engineering & Construction Company, Ltd. have the staff, the

Prepakt Concrete can be placed under ganisation and the finance to handle en- water with the same high results as ob- gineering projects of any magnitude and, tained above water as the Prepakt Mortar as part of their activities, they are in- will not separate in the water, but will troducing into Hong Kong a radically replace and lift the water. different concept of concreting which has been tried and proven all over America

ment.

or-

3.

Where the pile is cast in an uncased hole, the Intrusion mortar penetrates all irregularities in the surrounding material forming literally thousands of bearing areas along the entire length of the pile and providing the greatest possible frictional load-carrying capa- city.

The cost of materials, equipment, and labour for producing cast-in-place Pre- pakt piles is comparable to, and even less than, other methods for placing piles. The fact that dewatering is not required or desired for placing Prepakt concrete is an added economy feature.

and many other parts of the world, and Mortar are to fill the voids in the coarse Full information concerning the Prepakt which they feel will prove of utmost aggregate. to bind them together upon concrete methods can be obtained from value and benefit in Hong Kong. This is hardening of the mortar, and to consolid- the Ajax Engineering & Construction Co.. Prepakt concrete.

The mortar is so Ltd., 136 Hong Kong Hotel Building.

The primary functions of the Prepakt

ate the entire mass.

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