Comparison Study of Dynamic Elastic Moduli of Cement Mortar and No-cement Slag Based Cementitious Mortar Activated with Calcined Dolomite with Impulse Excitation Technique

Herry Suryadi Djayaprabha,Ta-Peng Chang,Jeng-Ywan Shih,H Akca,R Luca Tudorache,L Abdullah

doi:10.1051/matecconf/201818602004

Abstract

This paper presents the comparison of an experimental investigation on compressive strength and dynamic elastic moduli of mortars made of Ordinary Portland Cement (OPC) and ground granulated blast furnace slag (GGBFS) incorporating with calcined dolomite. Dolomite powder calcined at temperature 900°C emerged as a GGBFS activator for producing cementitious mortar binder. In this study, no-cement mortar is made by activating GGBFS with calcined dolomite by a fixed amount of 20 wt%. The compressive strengths and dynamic elastic moduli were measured at 7 and 28 days. Comparing with cement mortar, the compressive strength of no-cement mortar was found about 54.4 and 46.9% lower at ages of 7 and 28 days, respectively. Non-destructive evaluation of the dynamic elastic moduli was investigated by impulse excitation technique (IET). It measures the resonant frequencies of induced vibration signal in the flexural and torsional mode for determining the dynamic Young's modulus and the dynamic shear modulus. The Poisson's ratio was calculated by the dynamic Young's modulus and the dynamic shear modulus relationship. The results showed that the 28-day dynamic Young's and shear moduli of cement mortar were 31.91 and 14.43 GPa, respectively. The dynamic Young's and shear moduli of no-cement mortar were lower by 23.3 and 15.2% than that of cement mortar at the age of 28 days. The obtained results showed that the 28-day Poisson's ratio of no-cement mortar had a wider range between 0.177 and 0.209 than that of cement mortar which ranged from 0.180 to 0.185.

Highlights

Ordinary Portland cement (OPC), as a vital construction material, has reached worldwide annual production of 2.8 billion tonnes and expected to increase 4 billion tonnes per year [1]
The compressive strength of slag-dolomite mortar at ages of 7 and 28 days reached about 24.4 and 30.6 MPa, which was lower about 54.4 and 46.9% lower than cement mortar
The compressive strength of slagdolomite mortar proved to be increased with curing time due to ground granulated blast furnace slag (GGBFS) hydration process

Summary

Introduction

Ordinary Portland cement (OPC), as a vital construction material, has reached worldwide annual production of 2.8 billion tonnes and expected to increase 4 billion tonnes per year [1]. Approximately 5-7% of global carbon dioxide (CO2) emission originate from OPC production, ranging from 0.66 to 0.82 kg of CO2 emitted for every kilogram produced [2]. A large amount of industrial waste by-products such as ground granulated blast furnace slag (GGBFS) is being generated every year throughout steel industries. It is reported that the annual worldwide production amount of GGBFS is 530 million ton every year [3]. With the similar chemical and mineral composition to OPC, GGBFS can be potentially used as cement replacement. The usage of GGBFS as cement replacement reducing the CO2 emission and solving industrial byproduct waste disposal problem

Objectives

Results

Conclusion