Studies on Properties of Compressed Mud Blocks

Abstract

Stabilized and un-stabilized mud have been used as a building material since Indus valley civilization. Pozzolanic material such as burnt ash was used as stabilizers. As soil is most abundant, locally available material which makes it one of the most energy efficient and cost-effective building material. Extensive research on stabilized mud blocks was initiated at Indian Institute of Science, Bengaluru, for using of soil for making building blocks. The properties of compressed mud blocks are influenced by varying factors such as soil composition, moisture content, stabilizer content, compaction. Blocks are conventionally manufactured using Cinvaram, Astram, Itge Voth, Mardini, etc., having a compressive strength of blocks suitable for load bearing and non-load bearing walls. This technology is adopted for housing in many parts of India. This paper attempts to assess the properties of compressed mud blocks made by varying composition of soil, varying thickness and cement content. A total of 120 blocks are manufactured and tested to evaluate physical and mechanical properties such as dimensional stability, density, initial rate of absorption, water absorption and compressive strength. Compressive strength for blocks increased as the thickness was reduced. Increase in strength of 70 mm thick block was of the order 1.6 times as that of 100 mm thick block. As the fresh density of block was varied from 1.95 to 2.05 gm/cc, block compressive strength was found enhanced by 30%. Based on the mode of manufacturing, densification of the lower half of the block was more than the upper half of the block. When the sand-to-fines ratio is in the order of 1.5, highest compressive strength was achieved for stabilizing mud blocks.