Mechanical strength enhancement of lower hydraulicity cementitious solid wastes using anhydrite and pozzolanic materials

Journal Article · Mon Feb 01 04:00:00 EST 1999 · Cement and Concrete Research

DOI:https://doi.org/10.1016/S0008-8846(98)00187-2· OSTI ID:345092

Hong, S S; Lim, G G ^[1]; Lee, B K; Lee, B J; Rho, J S ^[2]

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1. Hoseo Univ., Chungnam (Korea, Republic of). Dept. of Chemical Engineering
2. Chungnam National Univ., Taejon (Korea, Republic of). Dept. of Fine Chemical Engineering and Chemistry

Mechanical strength enhancement was investigated for recycling lower hydraulicity inorganic solid wastes (HISWs) from five different building material manufacturing processes. The source materials are cement-gypsum composite board, cement fiber-reinforced board, calcium silicate board, corrugated slate, and sludge from wastewater treatment plants. Mineral admixture of 80% anhydrite as an ettringite-forming agent and 20% slag/fly ash as pozzolanic materials was added by weight ratio of cement. The specimens were prepared by the press molding method or without pressure, and then cured with steam at 80 C. The flexural strength of specimens with added HISWs did not meet the target standards for special use, regardless of source processes, addition ratio, and preparation methods without mineral admixture. The long-term mechanical strengths of compacted specimens were enhanced under 50 kgf/cm{sup 2} pressure with the addition of 10 wt% mineral admixture due to the stimulated pozzolanic reaction by slag/fly ash and the ettringite formation by anhydrite. The increased intensity of ettringite and CSH gel peaks was detected in X-ray diffraction patterns and confirmed by scanning electron microscopic analysis. The flexural strength was increased more than 30% and was not affected by the HISWs addition ratio. The water absorption ratio also was decreased with the addition of mineral admixture.

• OSTI ID: 345092
• Report Number(s): CONF-971201--
• Journal Information: Cement and Concrete Research, Journal Name: Cement and Concrete Research Journal Issue: 2 Vol. 29; ISSN 0008-8846; ISSN CCNRAI
• Country of Publication: United States
• Language: English

Related Subjects

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION
36 MATERIALS SCIENCE
ANHYDRITE
BUILDING MATERIALS
CEMENTS
COMPRESSION STRENGTH
FLEXURAL STRENGTH
FLY ASH
SLAGS
SOLID WASTES
WASTE PRODUCT UTILIZATION