Physical and Mechanical Properties of Sustainable Hydraulic Mortar Based on Marble Slurry with Waste Glass

Bartolomeo Megna,Antonino Valenza,Dionisio Badagliacco,Carmelo Sanfilippo

doi:10.3390/recycling6020037

Abstract

This paper aims to propose and characterize a sustainable hydraulic mortar entirely obtained by the reuse of waste materials, with marble slurry coming from quarries in the north-western Sicily and glass powder coming from a waste collection plant in Marsala (Province of Trapani). The first was used as raw material to produce the mortar binder by a kilning and slaking process, while the second was used as a pozzolanic additive. The chemical and morphological characterization of the marble slurry was done by XRD, FTIR, STA and SEM analyses. Glass powder was analyzed through particle size distribution measurements, XRD and standard pozzolanic tests. Hydraulic mortars constituted by slaked lime from kilned marble slurry and waste glass powder (LGS) were prepared beside commercial Natural Hydraulic Lime (NHL) based mortars (NGS) and air-hardening lime (LSS)-based mortars. Mechanical and absorption properties of the mortars were investigated as a function of the grain size of the glass powder by means of three-point bending and compressive strength tests, capillary uptake, helium pycnometry and simultaneous thermal analysis. The results demonstrated that the formulation LGS exhibits significantly improved mechanical and absorption properties compared to air-hardening mortars (LSS). It confirms the possibility of producing a more sustainable hydraulic mortar exclusively from waste materials for civil engineering.

Highlights

IntroductionA considerable amount of research has concerned the use of waste marble [1,2,3,4,5,6,7] and waste glass powders [8,9,10,11,12,13,14,15,16,17,18], separately, as additives to improve the physical and mechanical properties of mortars and concretes
The preliminary characterization of the materials revealed the opportunity to use marble slurry to produce an air-hardening lime that can act as a hydraulic binder when mixed with glass powder obtained from urban waste collection
Mechanical tests clearly showed good mechanical performance of the hydraulic binder based on air-hardening lime with better performance at lower grain size of the glass powder

Summary

Introduction

A considerable amount of research has concerned the use of waste marble [1,2,3,4,5,6,7] and waste glass powders [8,9,10,11,12,13,14,15,16,17,18], separately, as additives to improve the physical and mechanical properties of mortars and concretes. Waste materials causes a tremendous effect on air, water, vegetation, animals, human health and living conditions [19]. It is evident that the increase will pose a tremendous threat to environmental health in the absence of appropriate measures. It is well known that Portland cement production is one of the most environmental unfriendly process due to its high working temperature (1400–1500 ◦ C) and the massive consumption of raw materials such as limestone and clay. Cement production causes a considerable amount of greenhouse gas emissions both by carbonate decomposition and by fossil fuels combustion to heat the kiln. The extraction of raw materials used for its production is further an environmental issue and source of CO2 emissions [23]

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