# Short-Term and Long-Term Mechanical Properties of Lightweight Concrete with Sintered Aggregate

## TL;DR

This study examines the mechanical properties of lightweight concrete made with recycled sintered aggregate, focusing on both short-term and long-term performance.

## Contribution

The study provides new insights into the long-term mechanical behavior of lightweight concrete using standard testing methods.

## Key findings

- Short-term properties matched previous studies, but shrinkage and creep were significantly higher.
- Non-standard methods are unreliable for testing shrinkage and creep in this type of concrete.
- An unusual development pattern was observed for elastic modulus and axial tensile strength.

## Abstract

The aim of this work is to determine the short-term and long-term mechanical properties of lightweight concrete with relatively new sintered aggregate, as knowledge of these parameters is essential to the design of prestressed structures. The problem can be placed in a broader ecological context, because the aggregate comes from recycled power plant ash. This research study was planned based on two concrete mixtures that were already used in previous publications, as the aim of this work was to conduct comparative research by using other methods. In particular, the aim was to investigate the long-term properties of lightweight concrete by using standard methods and appropriate equipment, such as creep-testing machines. As a result of these studies, the secant modulus of elasticity, cylindrical strength, cubic strength, axial tensile strength, splitting tensile strength, bending strength, and shrinkage and creep strain were determined. This study confirmed the short-term properties of concrete obtained in previous studies but did not confirm the results regarding shrinkage and creep. These results turned out to be much higher, which means that these values should not be tested by non-standard methods. An unusual process of development of the elastic modulus and axial tensile strength was observed, and the reasons for these phenomena were described.