Influence of scoria and pumice on key performance indicators of Portland cement concrete

Journal article

Authors / Editors

King'ondu, Cecil

Research Areas

No matching items found.

Publication Details

Author list: Mboya HA, Njau KN, Mrema AL, King'ondu CK

Publisher: Elsevier

Place: OXFORD

Publication year: 2019

Journal: Construction and Building Materials (0950-0618)

Journal acronym: CONSTR BUILD MATER

Volume number: 197

Start page: 444

End page: 453

Number of pages: 10

ISSN: 0950-0618

eISSN: 1879-0526

Languages: English-Great Britain (EN-GB)

View in Web of Science | View on publisher site | View citing articles in Web of Science

Abstract

Cement industries have a huge CO2 signature that can be reduced in an effort to mitigate climate change via precise cement substitution with supplementary cementing materials (SCMs). The substituting materials and their amounts ought not to degrade the key performance indicators of concrete such as slump, flow, permeability, shrinkage, modulus of rupture, compressive, and tensile splitting strength. In this study, the influence of natural scoria (SN) and pumice (PN) binders on the key performance indicators of the fresh and hardened Portland cement (PLC) concrete was successfully examined. The performance indicators were tested at PLC substitution (with SN or PN) levels of 10, 20, 30, and 40% and the results compared to the control (CTRL) made of PLC only. The results show that 10% is the optimum substitution level for both SN and PN. The compressive strength, modulus of rupture, shrinkage, permeability, and thermal stability of the concrete were not compromised at this substitution level. The 28 days modulus of rupture, shrinkage, and compressive strength for SN and PN at 10% substitution were 6.0 and 6.4 MPa; 0.02 and 0.01 mm; 44.2 and 43.1 MPa, respectively. These compared remarkably well with 6.3 MPa modulus of rupture, 0.01 mm shrinkage, and 43.1 MPa compressive strength of the control. Moreover, SN and PN delivered higher % residual compressive strength of 59.2 and 57.8%, correspondingly, after subjecting the concrete to high temperatures of 600 degrees C, compared to 52.6% for the control. Likewise, the coefficient of permeability (K) for SN (5.2526E-08 m/s) was similar to that of PLC (5.35714E-08 m/s). At substitution levels higher than 10%, more than one key performance indicators were negatively affected. These results show the utility of SN and PN in reducing the amount of cement used in construction and thus the CO2 emission associated with cement industries while at the same time preserving the strength, permeability, thermal and volume stability and hence the durability of the concrete. (C) 2018 Elsevier Ltd. All rights reserved.

Keywords

Compressive strength, Flow, Modulus of rupture, Pumice, Residual strength, Scoria, Shrinkage, Slump

Documents