Evaluation of performances of volcanic-ash-laterite based blended geopolymer concretes: Mechanical properties and durability

The present project deals with the production of alkali activated concretes based on volcanic and calcined laterite under different curing temperatures (28-80 degrees C). A fraction of 0-40% calcined laterite was added to improve the reactive phase content and the resulting mixtures were labelled GL0, GL20 and GL40. The raw materials and hardened products were characterized using XRD, FTIR, optical microscopy, mechanical properties and durability. The results depicted that both calcined laterite addition (40%) and curing temperature (28-80 degrees C) have beneficial influences on the mechanical performance. At 28 days, flexural and compressive strengths ranged between 5.05-5.35 MPa and 39.68-48.80 MPa for GL40 specimens. Water absorption and porosity decreased from 7.23 to 4.51% and 9.70 to 6.01%; 16.70 to 10.32% and 22.20 to 13.80% respectively, for geopolymers GL40 and GL20 samples. Bulk densities values were 2398.44/2400.16; 2362.46/2364.16 and 2338.50/2340.20 kg/m(3) for GL40 and GL20 specimens respectively. After 19 weeks of sulfuric acid attack (pH = 1), a significant mass loss (1.28-6.22%) was measured in the geopolymer concretes. This behavior is linked to formation of a strong and compact matrix. The above-mentioned alkali activated concretes appear to be a suitable candidate for engineering applications in extreme conditions.

Automated summary

The study focused on producing alkali activated concretes using volcanic and calcined laterite under various curing temperatures, showing that the addition of 40% calcined laterite and curing temperatures of 28-80 degrees C positively impact mechanical performance. Characterization of raw materials and hardened products was conducted, demonstrating the suitability of these concretes for engineering applications in extreme conditions.