Effects of retempering on consistency and compressive strength of concrete subjected to prolonged mixing


Kırca Ö., Turanlı L. , Erdoğan T. Y.

Cement and Concrete Research, cilt.32, sa.3, ss.441-445, 2002 (SCI Expanded İndekslerine Giren Dergi) identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 32 Konu: 3
  • Basım Tarihi: 2002
  • Doi Numarası: 10.1016/s0008-8846(01)00699-8
  • Dergi Adı: Cement and Concrete Research
  • Sayfa Sayıları: ss.441-445

Özet

In this study, effects of prolonged mixing and four different retempering processes on some properties of fresh and hardened concrete, such as temperature, slump loss, and strength, were investigated. Two types of concrete mixtures with different compression strength having 15 cm initial slump were produced in a laboratory mixer. After mixing for 5 min at 20 rpm speed to ensure homogeneity, the mixing was continued at 4 rpm for a period of up to 4 h to simulate the prolonged agitation of ready-mixed concrete in truck mixers. Concrete samples were taken out of the mixer at the end of first, second, third, and fourth hour for estimating the effects of prolonged mixing on properties of fresh concrete. For restoring the initial workability, four different retempering methods were used and their effects on properties of concrete were investigated. Results show that compared to the untempered concrete mixtures, those tempered with solutions prepared by 3% or 4.5% solid superplasticizer by mass of retempering water had significantly less loss of 28-day compressive strength. © 2002 Elsevier Science Ltd. All rights reserved.