Physical, Mechanical, and Microstructure Characteristics of Ultra-High-Performance Concrete Containing Lightweight Aggregates

Abstract

This study explores and enhances the resistance of an ultra-high-performance concrete (UHPC) to explosive spalling under elevated temperatures. This study investigates the impact of lightweight aggregates (LWAs) on the mechanical and microstructural properties of the UHPC. Various UHPC specimens were created by replacing silica sand with LWAs in percentages ranging from 0% to 30%. The evaluation of these specimens involved assessing their compressive and flexural strengths, density, mass loss, shrinkage, porosity, and microstructural characteristics using scanning electron microscopy (SEM). This study provides valuable insights by analyzing the influence of lightweight aggregates on the strength, durability, and microstructure of UHPC. The results reveal that incorporating LWAs in the UHPC improved its flowability while decreasing its density, as the percentage of LWAs increased from 5% to 30%. Including 30% LWA resulted in a mass loss of 4.8% at 300 °C, which reduced the compressive and flexural strengths across all curing durations. However, the UHPC samples subjected to higher temperatures displayed higher strength than those exposed to ambient conditions. The microstructure analysis demonstrated that the UHPC specimens with 30% LWA exhibited increased density due to continuous hydration from the water in the lightweight aggregate. The pore size distribution graph indicated that incorporating more of the LWA increased porosity, although the returns diminished beyond a certain point. Overall, these findings offer valuable insights into the influence of lightweight aggregates on the physical and strength characteristics of UHPC. This research holds significant implications for developing high-performance, lightweight concrete materials.

Utilization of Bamboo Powder in The Production of Non-Asbestos Brake Pads: Computational Bibliometric Literature Review Analysis and Experiments to Support Sustainable Development Goals (SDGs)

“…In this context, pores can cause voids or pores in the composite, increasing the porosity of the material. This high porosity can reduce the density of the material and affect its mechanical properties, such as reducing strength and modulus of elasticity [85], [86]. Then, adhesion between the filler particles and the resin matrix can become weak if the particles are not covered properly.…”

Durability Improvement of Pumice Lightweight Aggregate Concrete by Incorporating Modified Rubber Powder with Sodium Silicate

“…Its engineering application value is that it can be added to concrete to play a skeleton role, which is widely used in the production of pumice lightweight aggregate concrete (PLAC) [1]. When the pre-wet pumice replaces the coarse aggregate by 30~40%, the PLAC processed has the advantages of low density, good compressive strength, split tensile strength, and flexural strength, which obviously improves the dynamic performance of the interfacial transition zone (ITZ) [2][3][4][5]. In this case, the failure strain of PLAC is larger than that of ordinary concrete, which indicates pumice aggregate has good plastic deformation ability [1].…”

“…Some engineering properties of RP-PLAC, such as mass loss, dynamic elastic modulus, and microstructure properties under freeze-thaw cycles, are evaluated [30]. Microtests including scanning electron microscopy (SEM), nuclear magnetic resonance (NMR), and a super-distance-of-field 3D microscope, are carried out [4,31]. The microscopic mechanism of MRP improving the resistance to freeze-thaw cycles for PLAC is deeply revealed.…”

A Micromechanical-Based Semi-Empirical Model for Predicting the Compressive Strength Degradation of Concrete under External Sulfate Attack

“…Compressive strength and its evolution are the most important parameters considered in the design and analysis of concrete structures [ 3 , 4 ]. The effect of an ESA on compressive strength has been reported in many experimental investigations [ 5 , 6 , 7 ].…”