Title: Effects of Sand Content, Superplasticizer Dosage, and Mixing Time on Compressive Strength of Mortar

Author(s): Virak Han, Soty Ros, and Hiroshi Shima

Publication: Materials Journal

Volume: 110

Issue: 1

Appears on pages(s): 23-32

Keywords: cement dispersion; compressive strength; limestone powder; mortar; sand content; superplasticizer.

DOI: 10.14359/51684363

Date: 1/1/2013

Abstract:
This study investigated the effects of unit sand volume, mixing time (MT) duration, and superplasticizer (SP) dosage on mortar compressive strength. The experiments were conducted on many mortar mixtures made of different water cement ratios (w/c), sand contents, MTs, and different limestone powder replacement ratios. Consequently, the experimental results suggested that a critical unit sand volume that caused a change of mortar compressive strength existed. When the unit sand volume in mortar exceeded the critical unit sand volume, the strength of the mortar increased and decreased in the case of the SP dosage of 0.3% or 0.6% and 0.8%, respectively. Moreover, it was identified that the critical unit sand volume was found to be 0.38 and 0.52 for a w/c of 0.3 and 0.6, respectively. Meanwhile, regardless of w/c, the optimum duration of MT was 3 minutes. The optimum SP dosage required for high cement dispersion leading to high compressive strength of mortar was found to be 1.0% and 1.18% for mortar with and without limestone powder, respectively.