Performance of natural polymers for stabilizing earth blocks

Abstract

Natural polymers have been tested for soil stabilization since prehistoric age. This study evaluated the behavior of seven natural polymers as earth stabilizer. Seven polymers were selected from Sri Lankan vernacular polymer technologies. Natural Polymers were extracted from plants and trees. And then mix designs were developed by mixing soil and natural polymers (5, 10, 15 and 20%) by the dry weight. Compressive strength was subjected to understand the initial performance of each natural polymer. And the series of performance tests were conducted to understand the engineering and mechanical performances.

The initial experiment shows only three natural polymers are suitable for stabilizing earth blocks such as pines resin, Dawul Kurudu, and sugarcane bagasse. And then different soil mix design experiment shows that natural polymers are good at gaining strength when soil particles are smaller (15% gravel sieve size 4.25–20 mm, 80% sand sieve size 0.425–4.25 mm, and 5% fine sieve size below 0.425 mm). Maximum compressive strength with pines latex was given as 2.65 N/mm2. It reached the construction material required the dry strength of 2 N/mm2 and wet strength of 1 N/mm2. Further studies should be conducted to understand the bond development and e values of selected polymer stabilized earth blocks.