Effect of Curing Environment on the Strength Properties of Cement and Cement Extenders

Abstract

Curing of cement based products such as concrete and mortar, is very important to achieve good strength and durable products. However the curing environment plays a pivotal role in the overall quality of cement based products in terms of strength development. ASTM C192 allows moist curing either in a fog room or under water. However, these must meet ASTM C511 which controls temperature, and specifically for water curing, the concentration of calcium ions in the curing solution. Unfortunately in many parts of the world, water curing literally means curing in tap water. This is done primarily because there is a lack of knowledge or ignorance regarding the mobility and roll of calcium hydroxide in the curing process. To illustrate the differences, in this study, straight ASTM Type I/II Portland cement and that mixed with powdered waste clay bricks as a cement extender were used to prepare two different batches of mortars. The chemical properties of the powdered waste clay brick met the ASTM C618 standard specifications for Class N pozzolans. Both mortar specimens were cured under two different environment comprising of either water and lime saturated water. Mortar specimens were tested for compressive strength at 3, 7, 14 and 28 days of either curing conditions. Test results indicated that mortar specimens cured in lime saturated water obtained higher strength than those cured in fresh water at all ages of curing. Statistical inference drawn from ANOVA testing showed that curing conditions had significant impact on strength development of the blended and unblended cement systems. The study recommends that testing of concrete and mortar samples and other research related works be performed in lime saturated water other than fresh water. * Corresponding author. M. Bediako et al. 34

Stabilization/solidification by hydraulic binders of metal elements from landfill leachate

“…The increase of CEM 1 percentage in the formulation induces the increase of the mechanical strength (compressive and flexural) from 30 to 70 MPa in the case of the compressive one. As expected, the curing time favors such properties, which agree with the hydration process (Bediako et al 2015). The observed increased compressive strength results in this study might be due to the organic content present in the Leachate, which might act as a dispersing agent, improving the dispersion of particles of cement and reducing clumping (Silva and Naik 2010).…”

Compressive Strength of Concrete Using Different Curing Methods

“…, were of the view that "moist sand" curing method was the most suitable curing method for concretes, "Drier curing" conditions was found by several researchers: Bingöl & Tohumcu, 2013;Ferreira et al (2012); Silva et al (2012) to perform worse than "wet curing" conditions. Bediako et al (2015) emphasized that the importance of curing is to primarily help cement achieve more complete hydration, whereas Jackson and Akomah, (2018), ascertained concrete needs to be cured for a maximum number of days to attain the maximum strength required. Shih-Wei Cho (2013) posited that silt with fine content of 5% and less is optimum for concrete strength and durability.…”

Effect of Scoria on Various Specific Aspects of Lightweight Concrete

“…The physical properties and chemical composition of this cement are listed in Table 1. Potable water meeting the requirements of ASTM C 1602-06 (2009) was used to mix the concretes, and saturated lime-water (Bediako et al 2015) was used to cure the specimens. The scoria extraction site, is located in Antsirabe, 167 km away in the southern part of Antananarivo, capital of Madagascar.…”