Strength behaviour of clay-cement concrete and quality implications for low-cost construction materials

Author(s): F. Solomon, S.E. Ekolu
Paper category: Conference
Book title: Concrete Repair, Rehabilitation and Retrofitting III (ICCRRR)
Editor(s): M.G. Alexander, H.-D. Beushausen, F. Dehn, P. Moyo
Print ISBN: 978-0-415-89952-9
Publisher: Taylor & Francis Group
Pages: 510- 511
Total Pages: 2
Language: English

Abstract: 
Incorporation of clay soil into concrete mixtures is one means of designing low-cost, low strength construction materials. However the influence of clay on material properties should be understood as it affects engineering performance. This paper argues that the use of concrete for low-cost cementitious building materials has special requirements. A significant demand exists for physical infrastructure in developing countries. Usually, concrete or mortar blocks of sufficient integrity for low-cost housing, are made from cement with clay-contaminated sand by artisanal builders.
The work presented is based on experimental results of a laboratory study done for clay-cement concrete material. The clay-cement concrete studied was designed to be a low-strength material and its properties fall between those of soil and concrete. Four control concrete mixtures of 350 kg/m3 CC (cementitious content) and w/cc (water to cementitious ratio) = 0.70, 0.75; 280 kg/m3 CC and w/cc = 0.80, 0.85 were prepared. Further mixtures were made by substituting the OPC (Ordinary Portland Cement) in control mixes with 10, 20, 30, 40, and 60% local raw clay. Compressive strengths were measured at ages of 7, 28, 56, 270, and 365 days for all the mixtures. The laboratory test results show that clay-cement concrete mixtures with a maximum of w/cc = 0.80 and 20 to 30% clay replacement can be suited to fulfill the requirement of strength and workability for low–cost, low strength applications such as including housing, roads and dams. Interestingly, clay-cement concretes gave higher strength performance factors at later ages than the corresponding plain cement concretes, suggesting a possible pozzolanic behaviour, however minimal. Further investigations are being undertaken to determine the behavior of the clay-cement mixtures through study of drying shrinkage, creep, abrasion resistance, and fluid permeability.

Online publication: 2014
Publication Type: abstract_only
Public price (Euros): 0.00