Title:
Characterizing the Effect of Admixture Types on the Durability Properties of High Early-Strength Concrete
Author(s):
Ragini Krishna Nikumbh
Publication:
Web Session
Volume:
Issue:
Appears on pages(s):
Keywords:
DOI:
Date:
10/23/2022
Abstract:
High early strength concrete (HESC) has numerous applications, where several methods are available to achieve its high early strength. Generally concrete mixtures are designed with high content of ASTM C1600 cement, low water to cement ratio, and a high dosage of superplasticizers. The strength properties of HESC have been widely studied, but limited documentation is made of its durability characteristics. With that objective, this study focuses on understanding its freeze-thaw resistance, surface scaling, autogenous & drying shrinkage; by examining the effect of using: (i) Low (LCCM), standard (SCCM), and high (HCCM) cement content of ASTM Type III and CSA/CSA blend cement; (ii) Different types and combinations of admixtures; (iii) Internal curing (IC) using light-weight aggregates (LWA). It has been observed that irrespective of cement content, both type III and CSA/CSA blend cement, achieved a minimum compressive strength of 1800 psi or flexural strength of 380 psi within 6 hours of mixing. Concrete mixtures designed with type III cement required using an accelerating admixture to achieve strength thresholds. HCCM exhibited concerns such as excessive shrinkage, higher heat of hydration, poor aggregate-past bond, and reduced permeability, while LCCM performed most satisfactorily. Comparing mixtures prepared with and without IC, LWA was very effective in mitigating excessive shrinkage. A well-entrained air-void distribution is known to be most effective in ensuring frost durability, but the complex chemistry between superplasticizers and higher heat of hydration associated with HESC makes it challenging to deliver a well-distributed air-void system.