Morphological and mineralogical analysis of treated Diss fibers and their effect on physico-mechanical characteristics of Diss concrete based on alternative binder

Abstract

The viability of using vegetable Ampelodesmos Mauritanicus (Diss) fibers to develop lightweight construction material was investigated in this paper. The objective of this work is to assess the physico-mechanical properties of Diss fibers reinforced concrete sample with fibers to binder volume ratio ranged from 0 (control specimen) to 4. In order to mitigate the inhibitory effect exerted by vegetable materials on binder hydration, Diss fibers were treated with hot water, while air lime-based binder has been selected to replace traditionally used cementitious binder. The most important part of this work is focused on the efficiency of using air lime-based binder to develop lightweight construction material containing Diss fibers. Air lime-based binder is the chosen variety of binder due to its abundance and low emissions from its manufacture. The experimental investigation of the chemical compatibility between treated fibers and binder through the hydration-test has shown the effectiveness of boiling water treatment on the modifications of morphological and mineralogical properties to overcome the inhibitory effect exerted when non-treated Diss fibers were used. The hardened specimen properties included dry density, porosity, compressive and flexural strengths, and elastic behavior have been studied. The results have indicated that despite a reduction in compressive strength, the reinforced specimen remains acceptable to be used in lightweight construction applications, as regards its compressive strength-value and lightening level. The flexural strength of reinforced specimen was found to be significantly enhanced. Depending on the amount of Diss fibers used in the mixture, it was found that the optimal addition of Diss fibers is in the range of 3 volumes content. The corresponding flexural strengthening rate has reached a value of 86.5 % higher, due to the several reinforcement mechanisms like the compaction process, Diss fiber bond reinforcement, and also the undisturbed development of hydrate components of air lime-based binder during hardening. Therefore, the addition of Diss fibers generates failure mode change of specimen from the brittle to ductile behavior, which results in improvement of deflection and toughness capacity.