Page 61 - ICJ Jan 2023

TECHNICAL PAPER COLLECTOR’S EDITION

understand the strength and behaviour of soil- (i) The compressive strength of soil-cement
cement mixtures, using local soils. Mitra (1951) blocks increases with an increase in cement
examined 9 types of local soils to determine their content and block density. The strength
suitability for soil-cement houses near Rangawan also increases with an increase in the
dam colony in India. One of his major findings is that curing period and the curing temperature.
sandy soils with 5 percent cement give adequate
strength and protection against weathering. (ii) Dimensional stability and resistance to
softening action of water can be improved
A majority of the earlier examples of soil-cement by cement stabilisation and densification.
buildings have rammed earth soil-cement walls.
The concept of soil-cement block masonry walls for (iii) Generally sandy and gravelly soils are
house construction was used in the construction suitable for cement stabilisation. Highly
of 260 houses at Bangalore, India (Madhavan and clayey soils demand more cement and
Narasinga Rao 1949). Probably this may be the first silty soils are difficult to compact. There
Indian example of soil-cement block masonry.
are very few attempts to specify upper and
lower bounds for soil grading.

Although the earlier studies indicate the
importance of sandy soils, there have been very
few attempts to recommend a range for sand and
clay fractions (except by Olivier and Mesbah 1987)
for satisfactory soil-cement block making. Also,
there is hardly any information relating the soil
composition to both strength and durability aspects
of soil-cement. Hence, the present investigation is
aimed at obtaining the desirable range of sand and
clay size fractions of soil, considering both strength
Fig 1 Grain size distribution curves of soils
and performance characteristics of blocks. Here,
Studies on the properties of machine pressed performance characteristics include behaviour
soil-cement blocks started after the fifties. There of soil-cement block when subjected to alternate
are a number of studies pertaining to several wetting and drying and dimensional stability due
parameters influencing the properties of soil- to moisture movement.
cement blocks (Fitzmaurice 1958, Spence 1975,
Bokhari 1976, Dietz 1979, Reddy 1983, Houben EFFECT OF SOIL GRADING/
and Cuillaud 1984, Olivier and Mesbah 1987). COMPOSITION ON STRENGTH OF

Table 1 gives a summary of major findings of some SOIL-CEMENT BLOCKS
of the earlier studies, regarding suitability of soils The compressive strength of soil-cement blocks
for cement stabilisation. required for any specific type of building will
mainly depend upon the expected masonry
The following points emerge from the earlier strength. Apart from cement quantity and block
investigations on soil-cement construction. density, soil grading has significant influence on

62 The Indian Concrete Journal | November 2018