Effects of clays on fracture properties of cement-based materials

Journal Article · Sat May 01 00:00:00 EDT 1993 · Cement and Concrete Research; (United States)

DOI:https://doi.org/10.1016/0008-8846(93)90022-2· OSTI ID:6609068

Moukwa, M ^[1]; Lewis, B G; Shah, S P; Ouyang, C ^[2]

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1. Master Builders, Inc., Cleveland, OH (United States)
2. Northwestern Univ., Evanston, IL (United States)

Effects of alumino-silicate clays on fracture properties of cement-based materials are reported in this paper. Two clays, illite and kaolinite, were used to replace 20% of Type 1 portland cement in different mixtures. Pore size distributions of hardened specimens were measured using mercury intrusion porosimetry, and compressive and fracture tests were conducted. It was found that when alumino-silicate clays are incorporated as substitutes for a fraction of the cement, the total porosity of hardened mixtures increases compared to that of hardened cement paste with no clay addition. The increase occurred primarily in the fraction of finer pores. However, the addition of clays decreased porosity for mortars. The addition of illite clay in cement-based mortars slightly decreased the compressive strength and the critical stress intensity factor (K[sub IC]), but increased the compressive toughness and the critical crack tip opening displacement (CTOD[sub C]). The replacement of 20% cement with 12% silica fume and 8% illitic clay increased the values of K[sub IC], CTOD[sub C] and the compressive strength. These results indicate that appropriate use of silica fume and alumino-silicate clays may make cement-based materials stronger and more ductile.

• OSTI ID: 6609068
• Journal Information: Cement and Concrete Research; (United States), Journal Name: Cement and Concrete Research; (United States) Vol. 23:3; ISSN 0008-8846; ISSN CCNRAI
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360603* -- Materials-- Properties
ALUMINIUM COMPOUNDS
ALUMINIUM SILICATES
BUILDING MATERIALS
CEMENTS
CLAYS
COMPRESSION STRENGTH
CONCRETES
CRACK PROPAGATION
FRACTURE PROPERTIES
ILLITE
KAOLINITE
MATERIAL SUBSTITUTION
MATERIALS
MECHANICAL PROPERTIES
MINERALS
MORTARS
OXYGEN COMPOUNDS
POROSITY
PORTLAND CEMENT
SILICATE MINERALS
SILICATES
SILICON COMPOUNDS
STRESS INTENSITY FACTORS