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Particle Size Distribution and Rate of Strength Development of Portland Cement
Author(s) -
Osbaeck Bjarne,
Johansen Vagn
Publication year - 1989
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.1989.tb06101.x
Subject(s) - fineness , particle size distribution , portland cement , cement , grinding , gypsum , materials science , sieve (category theory) , mineralogy , particle size , specific surface area , composite material , sieve analysis , clinker (cement) , particle (ecology) , mathematics , geology , chemistry , nanotechnology , biochemistry , oceanography , combinatorics , catalysis , paleontology
The fineness of a portland cement is a key factor in determining its strength development characteristics. A simple one‐parameter fineness characterization such as a Blaine value or a sieve residue is often inadequate for a precise evaluation of the influence of fineness on the strength development of cement, especially when comparing cements ground with different grinding equipment. Information on the whole particle size distribution (PSD) of the cement must be used. A mathematical model relating PSD to strength, based on comparison of cements made from the same basic materials (clinker and gypsum) but ground to different PSD, is presented. The model assumes that at a given time of hydration all particles have reacted to the same depth from the original surface. Integrating over the total PSD will give the degree of hydration for a specific size distribution. From a correlation between strength and degree of hydration, differences in degree of hydration can be converted into relative strengths. The applicability of the model is demonstrated by two examples. The first example compares two cements which are ground to different finenesses in the same mill. The second example compares two cements which are ground to the same specific surface area in two different mill systems, bringing about cements with PSDs of different shape. The depth of reaction values found to give the best description seems to be proportional to the square root of time of reaction, indicating a diffusion‐controlled hydration reaction.