Optimization of High-Performance-Concrete properties containing fine recycled aggregates using mixture design modeling

Dalila Benamara,Rebih Zaitri,Tounsia Boudina

doi:10.3221/igf-esis.57.05

Abstract

This investigation means to predict and modeling the fresh and hardened concrete behavior containing fine aggregates from concrete and brick wastes, for different recycled aggregates substitution rates. To succeed this, the design of experiments DOE method was used. It is observed that slump of recycled concrete is significantly influenced by the content in recycled concrete aggregates (RCA), natural sand (NS) and recycled brick aggregates (RBA), respectively.The compressive strength (CS) reaches a maximum value of 83.48 MPa with factors values of 25% RBA, and 75% RCA. And HPC’s based on RBA sand presented greater values of flexural strength at 7 days than HPC’s based on RCA sand, it was revealed that this is due to the RBA fines pozzolanic reaction and the production of new CSHs, which leads to better cement matrix densification.Under optimal conditions, themaximum desirability is 0.65, who has given HPC no added natural sand, by mixing recycled sands RBA (9.5%) with RCA (90.5%).The statistical terms result show that the expected models are very well correlated with the experimental data and have shown good accuracy.

Highlights

S everal research studies have been carried out in many countries for the purpose of studying the possibility of recovering construction and demolition wastes and use them as aggregates in new types of concrete [1,2,3,4,5,6,7,8]
Tab. 4 depicts the results of the experimental characterization tests carried out in the laboratory; these results were obtained on the basis of the developed mixture design
Through experimental tests and analyses of each formulation, which contains different factors, with various substitution rates, and using the mixture design approach, it was found that a good agreement exists between the results of the mathematical models and those of the experimental tests, which validates the various considerable data on the effects of each of the recorded parameters

Summary

Introduction

S everal research studies have been carried out in many countries for the purpose of studying the possibility of recovering construction and demolition wastes and use them as aggregates in new types of concrete [1,2,3,4,5,6,7,8]. The use of high-performance concretes (HPCs), thanks to their high strength, offers good long-term durability to construction structures and allows saving up to 40% of materials [12,13] For these reasons, the present work aims to investigate the effects of recycled sand from construction sites on -the physico-mechanical properties of high performance concretes. The present work aims to investigate the effects of recycled sand from construction sites on -the physico-mechanical properties of high performance concretes For this purpose, two types of recycled materials were been studied, namely recycled brick aggregates (RBA) and recycled concrete aggregates (RCA). To the best of knowledge, this is the first report using the modelling approach for mixture design with several statistical parameters, in forecasting the physical and mechanical properties of high performance concretes (HPCs) including recycled sand

Methods

Results

Conclusion