New Method for Proportioning Self-Consolidating Concrete Based on Compressive Strength Requirements

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Title: New Method for Proportioning Self-Consolidating Concrete Based on Compressive Strength Requirements

Author(s): Ghazi F. Kheder and Rand S. Al Jadiri

Publication: Materials Journal

Volume: 107

Issue: 5

Appears on pages(s): 490-497

Keywords: method; mixture proportioning; self-consolidating

Date: 9/1/2010

Abstract:
This study aimed to develop a new method for proportioning self-consolidating concrete (SCC). This method is capable of proportioning SCC mixtures with specified compressive strength, contrary to previous SCC proportioning methods that emphasized the fulfillment of fresh properties requirements more than strength requirements. In addition, no previous method considered the grading of aggregate in SCC mixtures (fineness modulus of fine aggregate and maximum size of coarse aggregate) as in conventional concrete (CC) proportioning methods, making a need for numerous trial mixtures to adjust the fresh and hardened properties of SCC. Two well-known concrete mixture proportioning methods, the ACI 211.1 method for CC and the EFNARC method for SCC, were adopted to develop the new method. The requirements of these methods were combined with certain modifications and a new method was proposed. In this new method, the actual range of compressive strength of the ACI 211.1 method was widened from 15 to 40 MPa (2145 to 5800 psi) to cover a wider range of strength (15 to 75 MPa [2145 to 10,875 psi]), thus covering both normal- and high-strength SCC mixtures. Thirty mixtures were tested to examine the validity of the proposed method; all these mixtures satisfied the fresh SCC requirements. Concrete strength results were in good agreement with the nominal design strength except for mixtures with a strength of 75 MPa (10,875 psi); these mixtures required a slight adjustment in the water-cement ratio (w/c). A modification on the proposed compressive strength and w/c relationship were introduced depending on data from previous literature on SCC.