Graduate Thesis Or Dissertation
 

The Pozzolanic Reactivity Test and the Properties of Portland Limestone Cement

Public Deposited

Downloadable Content

Download PDF
https://ir.library.oregonstate.edu/concern/graduate_thesis_or_dissertations/057420505

Descriptions

Attribute NameValues
Creator
Abstract
  • The pozzolanic reactivity test (PRT) is used to quantify the pozzolanic reactivity of supplementary cementitious materials (SCMs). The PRT computes reactivity by measuring heat release (Q) and calcium hydroxide (CH) consumption, as interpreted using thermodynamic modeling. The robustness of PRT is examined by experimentally varying CH-to-SCM ratio, solution-to-solid ratio, sulfate content, alkali type (Na vs. K), and alkali content. Furthermore, the similarities and differences between the PRT and the R3 test (ASTM C1897) are also evaluated. It is shown that the sulfates, as used in the R3 test, did not impact the siliceous reactions; but lead to the preferential formation of monosulfo-aluminates and ettringite with aluminous phases. The inclusion of carbonates, as used in the R3 test, also only impacted the aluminous reactions by forming hemi/mono carbo-aluminates over pozzolanic reaction products. Unlike PRT, the phase assemblage of the reacted products in the R3 test are not consistent and vary depending on the alumina content in the SCM. The PRT is recommended as robust tool to measure the degree of pozzolanic reactivity (DOR*) of the SCMs. A generalized relationship for the DOR* is also developed as a function of Q and CH consumption. This thesis also examines the performance of cementitious systems made of the clinker of typical sulphate resistant Type II/V cements (which have low aluminate content), LS, and SCMs. The work compares the heat of hydration, shrinkage, mechanical, electrical and transport performance of the paste and mortar made using OPC with the paste and mortar made using portland limestone cement (PLC) and OPC+LS cement with and without typical commercial SCMs (silica fume (SF), fly ash (FA), and slag (SL)). The heat of hydration, drying shrinkage, and flexural strength were investigated. When compared with OPC, the PLC and OPC+LS did not substantially affect either the extent of reaction at 7 days or the drying shrinkage. However, the degree of hydration of PLC and OPC+LS paste mixtures containing slag were approximately 10% higher than OPC paste mixtures containing slag at the age of 7 days. On the other hand, at early ages (less than 14 days) in the systems that did not contain SL or SF (i.e., plain and FA-containing systems), the flexural strength of the PLC and OPC+LS mortars are 15% and 20% lower than flexural strength of OPC mortars, respectively. The flexural strength was 7% greater at early ages for PLC and OPC+LS samples when combined with SL compared to corresponding OPC samples. The flexural strengths at later ages were similar for all mixtures. The porosity, formation factor, and pore connectivity of mortars were also examined. The porosity of both PLC and OPC+LS mortars were 4% higher than the porosity of OPC mortar due in part to the dilution of reactive clinker. The effect of dilution was offset with increased clinker reaction. The porosity of PLC+SCM and OPC+LS+SCM mortars was also 2% to 6% higher than the porosity of OPC+ SCM mortars. The mixtures containing SCMs with reactive alumina showed less of an increase in porosity since the limestone reacted to form carbo-aluminate reaction products. Despite the increase in porosity, there was no statistically significant difference between the formation factor of the PLC, OPC+LS, and OPC mortars without SCM. The PLC+SCM, OPC+LS+SCM, and OPC+SCM mortars had a higher formation factor than the plain OPC/PLC/OPC+LS mortars due to pore refinement. Pore refinement was also observed in PLC and OPC+LS mortars containing SCMs with reactive alumina. The results of this thesis indicate that PLCs (ASTM C595) can be used as a direct replacement for OPCs (ASTM C150) without any significant impact to hydration, shrinkage, mechanical, and transport related performance. PLCs are specifically recommended over OPCs when aluminous SCMs are incorporated in the system.
License
Resource Type
Date Issued
Degree Level
Degree Name
Degree Field
Degree Grantor
Commencement Year
Advisor
Committee Member
Academic Affiliation
Rights Statement
Related Items
  • Weiss Research Group
  • Isgor Rersearch Group
Publisher
Peer Reviewed
Language
Embargo reason
  • Pending Publication
Embargo date range
  • 2021-09-21 to 2022-04-21

Relationships

Parents:

This work has no parents.

In Collection:

Items

Thumbnail Title Date Uploaded Visibility Actions
file details Antara_Choudhary2021.pdf 2021-09-20 Public Download