Advances in Research 3(6): 548-557, 2015, Article no.AIR.2015.050 ISSN: 2348-0394 SCIENCEDOMAIN international www.sciencedomain.org The Effects of Curing Methods on Early-age Strength of Sustainable Foamed Concrete Alonge O. Richard1* and Mahyuddin B. Ramli1 1School of Housing, Building and Planning, Universiti Sains Malaysia, Penang, Malaysia. Authors’ contributions This work was carried out in collaboration between both authors. Author AOR designed the study, wrote the protocol, and wrote the first draft of the manuscript. He also managed the literature searches, analyses of the study and the experimental process while author MBR proofreads the manuscript. Both authors read and approved the final manuscript. Article Information DOI: 10.9734/AIR/2015/13373 Editor(s): (1) Francisco Marquez-Linares, Full Professor of Chemistry Nanomaterials Research Group School of Science and Technology University of Turabo, USA. (2) Enrico Franceschi, Department of Chemistry and Industrial Chemistry - University of Genoa Via Dodecanese 31-16146 Genoa, Italy. Reviewers: (1) Anonymous, Belarusian National Technical University, Belarus. (2) Kofi Agyekum, Department Of Building Technology, Kwame Nkrumah University Of Science And Technology (Knust), Ghana. (3) Anonymous, Linköping University, Sweden. (4) Anonymous, Chungnam National University, Korea. Complete Peer review History: http://www.sciencedomain.org/review-history.php?iid=758&id=31&aid=7113 Received 14th August 2014 th Original Research Article Accepted 28 October 2014 th Published 8 December 2014 ABSTRACT Curing is a process aimed at keeping concrete saturated or nearly saturated, so as to ensure complete hydration process of cement. For curing to be done properly, the temperature, duration and condition remain key factors. The rate of hydration is usually controlled by the quality and quantities of the cementitious materials present in the mix as well as the moisture availability and environmental temperature. Lightweight foamed concrete is regarded as a sustainable construction material in the construction industry. Some well known major setbacks such as low tensile and compressive strength, low flexural strength, fractural toughness and increase shrinkage as the ages grows, have been reported with this type of concrete. This work is directed at potential ways of increasing the compressive strength of this material by varying the curing method. Therefore, observing the effects of these variables on the eventual compressive strength of the samples in the early-ages of the concrete. The study was conducted using foamed concrete of 1200kg/m3- 1600kg/m3 density and at the water cement ratio of 0.45. No additives or admixtures _____________________________________________________________________________________________________ *Corresponding author: E-mail: [email protected]; Richard and Ramli; AIR, 3(6): 548-557, 2015; Article no.AIR.2015.050 were used in this study. The samples were cured using three methods i. e. Water, air and moisture. At the end of the study, the compressive strength of the samples was analysed and the result shows that the samples cured by moisture has the highest compressive strength at 28 days. Keywords: Sustainable construction materials; lightweight foamed concrete; curing method; early-age compressive strength. 1. INTRODUCTION concrete surface for special treatment of continuous wetting or comfortable temperature Sustainable building materials can be defined as and moisture contents. It can have a dominant materials that has an overall superior effect on the strength, quality control and performance in terms of some specified criteria comparative purpose of foamed concrete. It is such as locally produced and sourced materials, essential to established a clear cut curing regime transportation costs and environmental impact, for foamed concrete, a subject area that Brady et thermal efficiency, health consideration and al. [3] considered as deserving further studies. occupant needs, financial viability, recyclability, This curing system has been adjudged to be a waste and pollution, energy efficiency and source of strength gain through research studies. maintenance cost. The well known global warming has placed an insatiable demand in the Foamed concrete can be considered as a free construction industry relative to sustainable flowing, self compacting and versatile material materials and energy savings. The sustainable that consist of foam produced under pressure principle covers four areas which are social, from surfactants, fine aggregates as filler or economic, technical and biophysical. According some other cementitious materials and cement to Hossain and Inoue [1], sustainable with water for proper hydration process. It is construction has emerged as a paradigm to classified as a lightweight material in which air create a new kind of built environment: “one that void are entrapped in cement sand mortar. meets the needs of humans in the present Foamed concrete production can be done in two without limiting the ability of future generations to ways, it can either be by prefoaming method or meet their own needs”. In the word of Mohamad mixed foaming method. The preform method et al. [2], sustainability is the enablement to involves the process of preparing a stable foam maintain a state or nature as it is now in the solution separately and then blends with base present and without any negative effect or mix that has been prepared separately. While the hazard to the unborn generation potentials.The process of mixed foaming method involves the main aim of sustainability is to minimize the mixing of the foaming agent along the base mix environmental and ecological impacts, caused by constituents till there is proper mixing and then man on earth's surface resulting in cordial resulted in cellular concrete structure [3]. interrelationship of environment, economy and society. This practice has given rise to green The dry density of foamed concrete is usually buildings and hence green materials from which between 400 and 1600 kg/m3 and its they are made. compressive strength, which varies with density, can typically range between 1 N/mm2 and Curing can best be described as the process of 25N/mm2 at 28 days [3]. Foam concrete has a maintaining a satisfactory moisture content and satisfactory resistance to freeze/thaw effect and temperature suitable for complete early hydration sulphate attack. process in concrete. This is vital for the concrete strength development. It also has strong effects Many research works have been carried out on on properties such as durability, abrasion the physical, mechanical and chemical properties resistance, volume stability, strength, resistance of foamed concrete. Mechanical properties was to freeze and thaws as well as water tightness. dealt with by Kearsley [4], Liang and Chen [5], When the temperature and moisture content are Chen [6], Visagie and Kearsely [7] and Jones favourable, relatively rapid hydration is normally and McCarthy [8]. Durability properties by Brady recorded within the first few days after placement et al. [3], Nambiar and Ramamurthy [9], of the fresh concrete. This is contrary to Kearsley and Wainwright [10], Giannakou and hydration process that may arise as a result of Jones [11] and Davalos et al [12]. Functional the evaporation process. Hence, curing regime properties has been studied by Jones et al. [13], can be referred to as the period of subjecting Böttcher and Lange [14], Serrano-Perez et al. 549 Richard and Ramli; AIR, 3(6): 548-557, 2015; Article no.AIR.2015.050 [15], Kearsley and Mostert [16] and Ramamurthy perhaps, is as a result of its low compressive et al. [17]. strength development of both early and maturity ages in comparison with conventional concrete. In these past studies, the issue of low For instance, in building, the strength, load compressive strength of lightweight foamed carrying capacity and fire resistance are most concrete was essentially mentioned and curing important features to be considered. For effective effects was analysed but in all, the effect of prediction of the performance of foamed concrete curing regime at the early ages of foamed under certain load and ambient temperature, concrete produced without any additives or there must be a determination of the admixtures was very handy hence this research compressive strength at the early-age without study. any material strength aids like the addition of There are some handful research studies on the admixtures under different atmospheric curing methods of foamed concrete at maturity temperature to be depicted by curing method. age. Kearsley [4], in his study, concluded that The findings may give room for the determination water-cured specimens gave low strengths due of effective or appropriate admixture that can to the build-up of pore water pressure in the best suit the material. saturated microstructure of the foamed concrete. In another research study [18], it was found that 2. MATERIALS AND METHODS air-cured specimens at 40°C had higher strengths than those cured in water. 2.1 Materials Arif et al. [19] in their study, concluded that The constituent materials used in the production specimens cured in air had a higher strength of the lightweight foamed concrete, used for this than those sealed-cured, but stated that the study comprises of Ordinary Portland Cement, differences was specifically marked by the fine aggregates, portable water and stable foam content of PC and PFA mixes. Liang and Cheng from a protein based