Fresh and mechanical properties of roller compacted concrete containing Cationic Asphalt Emulsion admixture

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Date: Feb. 20, 2019
Publisher: Elsevier B.V.
Document Type: Abstract; Report
Length: 6,449 words
Lexile Measure: 1550L

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ABSTRACT

This research aims at evaluating the fresh and mechanical properties of RCC mixtures containing Cationic Asphalt Emulsion (CAE) as an admixture (0%, 2%, 4%, 6%, 8%, and 10% of the cement mass). Mixtures' proportions were obtained for each RCC mixture by calculating the maximum value on moisture-dry density curve according to modified proctor method. Then, Optimum Moisture Contents (OMC) and Maximum Dry Densities (MDD) were compared among the mixtures. Fresh properties of the RCC mixtures were also evaluated by Superpave Gyratory Compactor (SGC) while compressive strength, splitting tensile strength and flexural strength tests were employed for investigating the mechanical properties of the mixtures. Non-destructive ultrasonic test was performed in each cubic specimen to develop the compressive strength estimation model. Significance of the results' difference in each test considering the CAE content and curing age as sources of variance was assessed through Analysis of Variance (ANOVA) at 95% confidence level. Results indicated a significant improvement in fresh properties, and a significant drop in the mechanical properties when CAE is used as an admixture. In addition, Scanning Electron Microscope (SEM) images were used to evaluate the micro-structure of the mixtures. Results of this research indicate that 4% of CAE can reduce the amount of compaction energy required to reach the satisfactory field density. This improvement in fresh properties can decrease execution costs and lead to time saving. Furthermore, results of the mechanical tests indicate a reduction in mixture strengths due to the decreased cohesion between cement paste and the asphalt covered aggregates.

Keywords:

Roller compacted concrete

Fresh properties

Mechanical properties

Cationic Asphalt Emulsion

Rheology

One/two-way ANOVA

1. Introduction

RCC is known to be a proper option for construction of those pavements that are exposed to heavy and frequent loads. Since it doesn't need any reinforcement or forms, RCC has drawn the attention of designers and contractors as a fast pavement construction method. This type of pavement is placed and compacted with equipment similar to that of asphalt pavement and requires less time until traffic opening, compared to conventional concrete pavement. Technical advantages of this type of concrete over conventional concrete pavements are due to different rheological properties caused by aggregate grading type and mixture proportioning approach. The aggregate grading in this type of concrete contains a significant amount of fine aggregates and is in the aggregate grading range used for asphalt concrete [1]. Also, since RCC is mainly used for large-scale projects (e.g. dam and road construction), the dominant mixture proportioning approach usually seeks to minimize the cement paste's volume, and consequently, minimize the mixture manufacturing costs significantly. This type of aggregate grading and mixture proportioning will lead to mixtures totally different from conventional concrete mixtures, therefore, performing slump test to evaluate their workability is not possible (their slump is equal to zero). Thus, workability of RCC is measured utilizing the Vebe table and according to ASTM C1170 standard. In this method, the required time for a ring of mortar to be visible between the wall of the container and the surcharge...

Source Citation

Source Citation   

Gale Document Number: GALE|A577668177