Evaluation of mechanical properties of adobe chemically stabilized with "synthetic termite saliva”

Abstract

The raw mud brick (adobe) is a millenary technology that awakens a wide interest in ecologic and non-conventional constructions. Some advantages are low cost, thermal comfort and minimum environmental impact. For better use, it is important to improve their mechanical properties. Dynasolo DS-328® is a chemical stabilizer used in soil compression for road paving and it is similar to termite saliva. This composition is based on vegetal oils. It is a high-concentrated liquid product, water soluble, non-toxic, non-corrosive, and non-flammable. The cohesive properties promote the investigation about the incorporation of this product in adobe composition. Therefore, this work aimed to evaluate synthetic termite saliva" incorporation to adobes at four different concentrations: 1:2000; 1:1500; 1:1000 and 1:500. The reagent is an aluminum sulfate at 1:5000 for all treatments. The soil is a Red Latosol cambisol corrected to 50% fine sand fraction. Soil bulk density, particle density and total pore volume were: Ds = 1.42 kg/dm3, Dp = 2.62 kg/dm3 and VTP = 45.8%. The soil Atterberg limits were: LL (liquid limit) 55.44%; PL (plastic limit) 34.58%; SL (shrinkage limit) 21.67%; and PI (plasticity index) 20.86%. The ideal moisture content was variable, ranging from 50% to 40% according synthetic termite saliva" increase. Adobes were submitted to compression and bending resistance tests. This research confirmed that synthetic termite saliva" incorporation improved the adobe compressive resistance and chose the treatment 1:1500 because it increased 20% this property.