Reactivity Effect of Calcium Carbonate on the Formation of Carboaluminate Phases in Ground Granulated Blast Furnace Slag Blended Cements

Walid Deboucha,Yassine El Mendili,Nordine Leklou,Aurélie Fabien,Alexandra Bourdot,Mahmoud N Hamdadou,Stéphanie Gascoin,U Johnson Alengaram,Nassim Sebaibi

doi:10.3390/su13116504

Abstract

The reactivity effect of calcium carbonate, present in ground oyster shells and limestone filler, on the formation of carboaluminate phases in ground granulated blast furnace slag blended cement pastes was reported in this paper. Six different binary and ternary blended cement pastes were prepared using ground granulated blast furnace slag, ground oyster shells and limestone filler with different replacement levels (from 5 to 35%). The carboaluminate formation was assessed and quantified directly using X-ray diffraction (XRD), and indirectly by following the aluminate phase’s reaction (heat flow) and consumed calcium carbonate using Isothermal Calorimetry (IC) and Thermogravimetric Analysis (TGA), respectively. Further, the overall reaction degree calculated based on TGA results and the compressive strength were determined to support the findings obtained. The results revealed that the calcium carbonate present in ground oyster shells is more reactive when compared to that present in limestone filler, where more formed hemi- and monocarboaluminate phases were observed in mixtures containing ground oyster shells. An enhancement in compressive strength and overall reaction degree was observed by adding 5% ground oyster shells as cement replacement.

Highlights

Introduction iationsThe need for reducing energy consumption and CO2 emission caused by cement production has become an increasingly important issue in recent years [1,2,3,4]
Calcium carbonate contained in LF or ground oyster shells (GOS) to form carboaluminate phases was followed by measuring the heat flow using Isothermal calorimeter TAM AIR device
The results obtained by using different techniques to assess the formation of carboaluminate phases in binary and ternary blended cement pastes based on GGBFS, LF and GOS

Summary

Introduction

The need for reducing energy consumption and CO2 emission caused by cement production has become an increasingly important issue in recent years [1,2,3,4]. The use of mineral additives as clinker or as cement replacement should help in achieving environmental and economic advantages [5,6], and should help in achieving the required technical performance [7,8]. Natural or byproduct materials, are widely used in blended cement systems to improve the chemical properties, i.e., hydration reactions, the mechanical properties such as strength, and the durability of concretes [9,10]. Are the most commonly used for cement replacement. The main advantage of the use of LF is the early ages compressive strength improvement by enhancing the hydration rate.

Methods

Results

Discussion

Conclusion