Experimental Investigation on the Application of Ultra-Rapid-Hardening Mortar for Rigid Small Element Pavement

Abstract

Natural stones have been typically used as a paving material in historically conserved areas due to architectural aesthetic aspect and environmental impact. However, they have been traditionally suggested in light traffic volume due to the defects caused by the increased traffic loading and volume. The failures can lead to diverse problems such as losing flatness, severe damage to both vehicles and pedestrians, high traffic congestion, maintenance cost, etc. In order to overcome these obstacles, ultra-rapid-hardening (URH) cement for rigid small element pavement (SEP) was implemented as both jointing and laying course materials. Additionally, their mechanical properties were investigated according to BS 7533-4 and National Stone Surface (NSS) in the UK. Preliminarily, the proper mix mortar design was found by comparing design parameters. The compressive and flexural strength of the joint and laying course by age was verified, and the results in early-age stage were satisfied with the requirements. The adhesive and shear strengths depending upon the width of the joint were determined, and from the test outcomes, the optimal thickness of the joint was found as 15 mm. Furthermore, by contrasting the compressive strength of the laying course with the punching shear strength, the shear strength regarding joint states was increased by up to 134.3% (fully restrained), 127.9% (semirestrained), and 107.2% (non restrained). This investigation would be possible to use as baseline data for an evaluation of the long-term performance of rigid SEP.