Title:
Performance Evaluation of United States Regional Portland Limestone Cement–Calcined Clay Blends (Prepublished)
Author(s):
Thien Tran, Paola Huynh, Daniel Benkeser, Kimberly E. Kurtis, Kyle A. Riding, Kejin Wang, and Maria C.G. Juenger
Publication:
Materials Journal
Volume:
Issue:
Appears on pages(s):
Keywords:
calcined clay; gypsum; LC3; CC·I·L; Portland limestone cement
DOI:
10.14359/51750665
Date:
4/9/2026
Abstract:
Limestone calcined clay cement (LC3) has the potential to provide high clinker replacement in cement blends while providing excellent engineering properties and durability with low environmental impact, but such blends of clinker, limestone, and calcined clay are still in the industrial trial stage in the United States (US). In this study, it is proposed that sources of calcined clay (C), Type IL portland cement (IL), and additional limestone powder (L) can be blended into a “CC·I·L” cement to speed up the implementation of LC3-like systems in the US by combining already commercially available components during concrete mixing. In this investigation, regional CC·I·L blends were prepared using ASTM C595 Type IL cements and calcined clays, replacing 20% - 30% of the cement, from suppliers in the east, west, central, and mountain areas of the US, with additional ground limestone to reach a total limestone content of up to 15% by mass of the total cementitious system. To investigate the feasibility of this approach, fresh properties, early and late age performance, and durability of pastes and mortars made with the CC·I·L blends were examined and compared to ASTM C595 standard performance requirements and performance of regionally available Type IL cements. The results showed that 30% calcined clay and 15% limestone can be used to produce CC·I·L blends in each studied region to meet the ASTM C595 strength requirements. However, gypsum adjustment up to 5.0% was necessary to address undersulfation of CC·I·L blends in some of the regional blends. The results demonstrate the feasibility of using CC·I·L in the US without intergrinding, by taking into account key design factors such as the reactivity of calcined clays, sulfate balance, performance, durability, and possible environmental impact.