Effect of Aggregate Size on Strength Characteristics of High Strength Lightweight Concrete.

Hui Wei,Xi Liu,Yang Liu,Tao Wu

doi:10.3390/ma13061314

Abstract

Effects of aggregate size on the mechanical properties of lightweight concrete (LC) were investigated. Four gradings of lightweight aggregate (LWA) were designed and used to prepare the specimens for compressive strength, splitting tensile strength, and flexural strength tests. An estimating method for compressive strength of LC was then established. The compressive strength of tested LC was up to 95 MPa at 90-day curing time. The test results suggested that the absence of medium-size particles decreased the compaction of LC, therefore the density and compressive strength were negatively affected. Specimens having single size of aggregate showed lower splitting tensile and flexural strengths than that having three sizes of LWA. The parameters of the estimating model were determined according to the test results, and the compressive strength predictions of estimation model were compared with the results from other literature.

Highlights

Lightweight concrete (LC) has been progressively used in structures such as large-span bridges, high-rise buildings and offshore oil platforms, owing to its superior characteristics in density, specific strength and durability [1,2]
This phenomenon was observed by Alengaram et al [10], and it was attributed to the absence of medium-sized particles, leading to a poor compaction of fresh concrete, which can be confirmed by comparatively higher densities of LC-IIand LC-IV
Compared with normal weight concrete (NWC), the low-strength lightweight aggregate (LWA) is the weakest phase in LC, the crack propagation was considered to appear straight across the LWA in general

Summary

Introduction

Lightweight concrete (LC) has been progressively used in structures such as large-span bridges, high-rise buildings and offshore oil platforms, owing to its superior characteristics in density, specific strength and durability [1,2]. Lightweight aggregate (LWA) is crucial for the properties of LC, since the main reason for the lightweight feature of LC was the light and porous LWA which differs from the denser structures of aggregates in NWC. In addition to the filling role that aggregates play, the mechanical frame of concrete is affected by aggregates [5]. It is well known that the grading of aggregates in concrete affects the mechanical properties of NWC [6,7] in terms of the compaction and bond properties of concrete. The different aggregate size of LC could represent a different path of fracture, and the properties of LC can be influenced

Methods

Results

Conclusion