Self Curing Concrete with Light Weight Aggregate

Abstract

As water is becoming a scarce material day-by-day, there is an urgent need to do research work pertaining to saving of water in making concrete and in constructions. Curing of concrete is maintaining satisfactory moisture content in concrete during its early stages in order to develop the desired properties. However, good curing is not always practical in many cases. Curing of concrete plays a major role in developing the concrete microstructure and pore structure and hence improves its durability and performance. Keeping importance to this, an attempt has been made to develop self curing concrete by using water-soluble Polyethylene Glycol as self-curing agent and light weight aggregate as Granite. The aim of this investigation is to study the strength and durability properties of concrete using water-soluble Polyethylene Glycol as self-curing agent. The function of self-curing agent is to reduce the water evaporation from concrete, and hence they increase the water retention capacity of concrete compared to the conventionally cured concrete. The use of self-curing admixtures is very important from the point of view that saving of water is a necessity everyday (each one cubic meter of concrete requires 3m3 of water in a construction, most of which is used for curing).In this study, compressive strength and split tensile strength of concrete containing self-curing agent is investigated and compared with those of conventionally cured concrete. It is found through this experimental study that concrete cast with Polyethylene Glycol as self-curing agent is stronger than that obtained by sprinkler curing as well as by immersion curing. In the present study, the affect of admixture (PEG 400) on compressive strength, split tensile strength and modulus of rupture by varying the percentage of PEG by weight of cement from 0% to 0.2% were studied for M20. It was found that PEG 400 could help in self curing by giving strength on par with conventional curing. It was also found that 0.1% of PEG 400 by weight of cement was optimum for M20 grade concretes for achieving maximum strength without compromising workability. Concrete derives its strength by the hydration of cement particles. Hydration isn't a momentary action but a long time process. Even if higher w/c ratio is used, water gets evaporated into the atmosphere leading to insufficient hydration especially in the top layer. Hence extra water needs to be added i.e., curing. Each 1m 3 of concrete requires about 3m 3 of water for construction most of which is for curing (conventional). If curing is neglected, the quality of concrete will experience a sort of irreparable loss. A self-curing concrete primarily comprising coarse aggregates, fine aggregates, cement, and mixing water, and further comprising a self-curing agent added during mixing, wherein the self-curing agent absorbs moisture from air and then releases it into the concrete, thereby achieving self-curing without external curing method after placing, wherein a specific amount of the self-curing agent is added to the concrete such that a 10% higher compressive strength than that of concrete without curing is achieved, wherein the added solid amount of the self-curing agent is about 0.1%-0.2 wt. % of cement weight of the concrete, wherein the added self curing agent comprises polyvalent alcohol selected from the group consisting of xylitol, sorbitol, phytosterols and butylene glycol. 1. Potential Materials  Cement of 53 Grade  Fine Aggregate  Coarse Aggregate  Waste Granite As Coarse Aggregate Replacement  Peg 400 Polyethylene Glycol, Paraffin Wax, Acrylic acid are some of the commonly available hydrophilic materials in market. 2. Results  Water retention for the concrete mixes incorporating self-curing agent is higher compared to conventional concrete mixes, as found by the weight loss with time.  Self-curing concrete resulted in better hydration with time under drying condition compared to conventional concrete.  Performance of the self-curing agent will be affected by the mix proportions mainly the cement content and the w/c ratio.  Use of Polyvinyl alcohol (0.48% by the weight of cement) as self-curing agent Provides higher compressive, tensile as well as flexural strength than the Strengths of conventional mix.  Increase in the Percentage of polyvinyl alcohol results in the reduction of weight loss.  Durability of self-curing concrete to sulphate salts and chloride induced corrosion is needed to be evaluated.  The result also showed that compressive, tensile and flexural strength of self-curing concrete is found to be higher than conventional concrete.  The self-curing concrete is a self-consolidating concrete and a high performance concrete. 3. Applications  Water scarcity  Labor cost is high  Water contains high fluoride content  Inaccessible structures in difficult terrains 4. Self-Curing Concrete 4.1 Introduction Most of the concrete that is produced and placed each year all over the world already does self-cure to some extent. Some of it is not intended to have anything done to its exterior surface, except perhaps surface finishing. Yet the concrete's ability to serve its intended purpose is not significantly reduced.