Durability of Reinforced Concrete with Additions of Natural Pozzolans of Volcanic Origin

Abstract

In this work, the properties of concrete modified with dosages of natural pozzolans (NP) in substitution of cement or superfine aggregates were evaluated. Proportions of 20/80 pozzolan/cement or pozzolan/superfine aggregates were selected for the additions of quarry and tuff pozzolans. Pozzolanic activity, durability, compressive strength, characteristic resistance, settling consistency, density, electrical resistivity, depth of water penetration, accessible porosity, and carbonation and chloride penetration were determined for the resulting concrete mixtures, and they were subsequently compared to the values obtained for the reference concrete batches without additions. The results of the cementitious mixtures supplemented with tuff (PZT) and quarry (PZQ) pozzolans, expressed in mmol/L, are consistent with the pozzolanism test, with [Ca(OH)2]/[OH−] ratios at 7 days are 6.03/60.19 for PZQ and 1.78/92.78 PZT. In addition to the pozzolanic activity at these dosages, the characteristic resistance and durability parameters required by EHE-08 were verified. Particular attention was given to the determination of the diffusion of chloride ions, introducing an instrumental modification of the accelerated integral method. The modification provides values of diffusion coefficients similar to those obtained by the other methods with the advantage of greater stability and quality of the measurement.

Volcanic Ash from the Island of La Palma, Spain: An Experimental Study to Establish Their Properties as Pozzolans

“…Note also that the low sulphate and chloride content determined for these VAs are significantly below 0.1% and 4%, respectively, which is a determining factor in demonstrating their quality as a pozzolan [45]. A wide variety of natural pozzolans show similar behavior [46].…”

Study on microstructural and mechanical properties of cementitious materials composed of fly ash and dacite powder

“…proposed to add rice husk ash into cementitious materials as an admixture, studied the compressive strength, splitting tensile strength and flexural strength of the materials and made a microstructure evaluation, and proposed that this material has the potential to prepare high-performance concrete. Santana et al (Santana et al, 2022) proposed to add natural Volcanic ash to modify concrete and studied the activity, durability, compressive strength and other aspects of Volcanic ash. They found that natural Volcanic ash materials have a negative impact on the life of concrete (Sun et al, 2022).…”