Acknowledgment
We acknowledge the valuable contributions of R. R. Grissom, W. R. Hnot, Werner Kurzbuch, Mortimer May, E. K. Matthews, J. P. McDermott, Aaron Preiser, J. F. Rakszawski, Roman Slysh, Kamil Sor, J. D. Turner, and A. H. Wunderlich. literature Cited Figure 8. BMX demonstration houfe
McKesson, C. L., Watts, V. E. (to Standard Oil Go. of Calif.), US. Patent 2,297,063 (1942). Rogers, D. T., Munday, J. C. (to Esso Research & Engineering Co.), U.S. Patent 3,287,146 (1966a). Rogers, D. T., Munday, J. C. (to Esso Research & Engineering Co.), U.S. Patent 3,274,016 (1966h). Rogers, D. T., Munday, J. C. (to Esso Research & Engineering Co.), U S . Patent 3,281,256 (1966~). Rogers, D. T., Munday, J. C. (to Esso Research & Engineering Co.), U S . Patent 3,243,311 (1966d). Rogers, D. T., Munday, J. C. (to Esso Research & Engineering Co.), Canadian Patent 759,865 (1967a). Rogers, D. T. Munday, J. C. (to Esso Research & Engineering Co.), U.S. Patent 3,330,677 (196713). Rogers, D. T., Munday, J. C. (to Esso Research & Engineering Co.), U S . Patent 3,387,982 (1968). United Nations, “Science and Technology for Development,” UN 63.1.24 (1963). RECEIVED for review September 27, 1968 ACCEPTED February 4, 1969.
Figure 9. Application of BMX thin-line mortar bond
Division of Petroleum Chemistry, 156th Meeting, ACS, Atlantic City, N. J., September 1968.
ASPHALT-STABILIZED BUILDING BLOCKS G E R A L D 1. K I M . M O N S ’
International Institute of Housing Technology, kxsrw State College, Fxsno, Calif. 93726
R.
1. F E R M A N D
R O B E R T MATTESON’
Cheuron Research Co., Richmond, Calif. 94802 Unstabilized earth is still the most common material for home Construction in many countries. Waterproofing with asphalt can greatly improve such construction, but is now practiced only in the United States. Various types of asphalt and other stabilizers are compared for making earth blocks.
BASED, upon
recent data (United Nations, 19651, the houslng requirements of the world are currently of the order of 758,000,000 dwelling units. Ten years from now the projected figure is 913,000,000 units, or an increase of 155,000,000 dwellings. In Asia, Africa, and Latin America, the requirements in the next 10 years will be for 111,000,000 new units. In these three areas of the world a high proportion of the houses are made of mud, usually ‘Present address, College Park Corp., Indianapolis, Ind. ‘Present address, 200 Wayne Ave., Alamo, Calif. 250
l & E C P R O D U C T RESEARCH A N D D E V E L O P M E N T
in the form of sun-dried bricks. The authors estimate that over half the people in these parts of the world live in houses of this type. The requirements for the next 10 years, to the degree that they are met, will he filled largely with the soil block house. Low per capita income is a common problem of the emerging nations. Hence, a building material must be low cost, waterproof, even for use in desert areas, and, finally, must possess strength, mainly in compression. The stabilized, sun-dried soil brick meets all of these qualifications. In fact, the common sun-dried hut
unstabilized brick hlas done so on all points but waterproofing for thousands of years. This study was conducted at the International Institute of Housing Technology to provide additional information on asphalt-stabilized rjoil bricks and to investigate other stabilizer materials. The soil used in all experiments was obtained from a Fresno manufacturer of adobe bricks. X-ray analysis indicated the presence of about 20% total illite and kaolinite clays. Montmorillonite was absent. The soil was free of water-soluble salts. The sand equivalent (State of California, 1964) was 51.2. Thus, silt and clay accounted for about 49% of the soil. The wet sieve analysis was as follows: Screen Size
u.s.
Cumulative
Standard Series
Mm.
8 16 30 50 100 200
2.38 1.19 0.590 0.297 0.149 0.074
wt. %o
Passing
99.3 95.3 81.3 63.3 51.2 44.4
The stabilizers, in addition to portland cement, that were used in the experiments reported are described in Table I. With these stabilizers, test specimens in the forms of cylinders and blocks were made from the soil mentioned above. Some work was done on floor tiles, floor slabs, and lightweight roof sections. Experimental Procedure
Cylindrical Specimens. The bulk of the experiments centered upon making 2- by 2-inch cylinders of soil-stabilizer mix. Enough unstabilized cylinders to give a firm base point for strength comparisons were fabricated. At the start of an (experiment a given amount of dry soil (usually from 2 to 10 pounds, depending upon the number of specimens t o be made) was accurately weighed and charged to the mixing bowl of a Triumph 20-quart mixer. Sufficient water was added to the soil to assure good mixing, but still maintain the mixture below the liquid limit. In a typical mixture using asphalt emulsion, prewetting water was about 12% by weight of dry soil. The weighed stabilizer was added to the prewetted soil. In each case the amount of stabilizer was calculated as a percentage, by weight, of the dry soil. After thorough mixing, the resultant mud was placed by hand in the appropriate forms. The 2- by 2-inch forms were cut from plastic tubing and wetted with water before filling with the mud. Occluded air was worked out of the specimens with the fingers. The mold form was immediately removed from the specimens. Subsequently, the samples were dried at room temperature for 24 hours and then placed in an oven a t 140"F. for 96 hours. When portland cemlent was used as the stabilizer, the samples were cured 28 days in a humid atmosphere. The dried specimens were then capped a t both ends with plaster of paris and tested to destruction under compression. Block Specimens. In making rectangular blocks, various forms were used; they were usually 4 by 4 by 4 or 4 by 4 by 16 inches, depending upon the use for which
Table 1. Properties of Soil Stabilizers
Asphalt Emuhorn Classification (Asphalt Institute) Emulsifier type Asphalt content, wt. % Asphalt penetration a t 77" F. (ASTM test D5,lOO g., 5 sec.) Asphalt softening point, O F. (ring and ball method) Av. particle size, microns p H of aqueous phase
Experimental
Commercia1
1
2
SS-lh Anionic 60 55
Anionic 53.6 70
Anionic 45 100
103
200
5 11
10 9.5
90
