More About Cementitious Materials

About SCM

PREDICTING THE ALKALI CONTRIBUTION OF SCMS TO CONCRETE PORE SOLUTION

 

(SCMs) are often used in concrete to reduce the risk of alkali-silica reaction 

Supplementary cementitious materials (SCMs) are often used in concrete to reduce the risk of alkali-silica reaction (ASR). This is primarily through dilution of the alkalis contributed by Portland cement and binding of alkalis as a result of pozzolanic reaction. Some SCMs, however, contain a high level of total alkalis, and these may be soluble, leading to increased pore solution pH and reduced efficiency in mitigating ASR. This may be especially problematic for many non-conventional and rapidly growing SCMs, such as volcanic ashes, marginal coal ashes, and ground glass, having total Na2Oeq > 3.0%wt. This paper presents a new soluble alkali test to quantify the soluble fraction of alkalis in SCMs. The test was applied to 14 SCMs including coal ashes, volcanic ashes, calcined clays, and ground glass, and their alkali release was monitored for 90 days. The results are compared with ASTM C311’s “available alkali test.” Additionally, the pore solution of cement pastes made using 11 of these SCMs were extracted and analyzed over 90 days.

The findings indicate that a considerable fraction of the total alkalis in SCMs is soluble in concrete’s pore solution. However, the pozzolanic reaction can bind most of the dissolved alkalis, resulting in a net alkali sink/reduction for the majority of the tested SCMs. A regression analysis of the results revealed that the pore solution [OH] reduction by an SCM can be estimated based on the SCM’s pozzolanic reactivity, soluble alkali content, and Ca/(Si+Al).

Read More

Farshad Rajabipour /  Professor of Civil Engineering, Pennsylvania State University, fxr10@psu.edu.

Mohammadreza Sharbaf   /  Ph.D. Student of Civil Engineering, Pennsylvania State University, m.r.sharbaf@psu.edu.

Concrete In Practice 

In its most basic form, concrete is a mixture of Portland cement, sand, coarse aggregate and water. So what sounds simple is really an exact science of mixtures and byproducts. The attached document explains in detail the science of concrete and how SMC’s enhance modern day concrete.

Industry News

Purebase featured in a business spotlight in the Ledger Dispatch

Purebase featured in a business spotlight in the Ledger Dispatch

Purebase Corporation was featured in a business spotlight column in the Ledger Dispatch, Amador, and Calaveras Objective Regional Newspaper. The Ledger Dispatch is the publishing newspaper for the same county in California that Purebase Corp resides in, and the...

Purebase promotes Joe Thomas to advisory board chairman

Purebase promotes Joe Thomas to advisory board chairman IONE, CA, MARCH 13, 2024 (GLOBE NEWSWIRE) — Purebase Corporation (OTCQB: PUBC), a natural resource development company headquartered in Ione, California, announces the appointment of Joseph Thomas as chairman of...

Purebase announces new Chief Financial Officer

 Purebase announces new Chief Financial Officer  IONE, CA, DECEMBER 14, 2023 (GLOBE NEWSWIRE) — Purebase Corporation (OTCQB: PUBC), a diversified resource company, headquartered in Ione, California, announces the appointment of Stephen Gillings, MBA as Chief Financial...

Purebase Corporation Enters into a Material Definitive Agreement

Purebase Corporation Enters into a Material Definitive Agreement IONE, CA, November 8, 2023 – Purebase Corporation (OTCPK: PUBC), (“Purebase”) Purebase Corporation entered a Second Amendment to the Materials Extraction Agreement (“Agreement”) on November 1, 2023 with...

Subscribe To The Newsletter

Subscribe

* indicates required

By providing your e-mail address, you are consenting to receive press releases and other information concerning Purebase Corporation and its affiliates and partners. You may withdraw your consent at any time.