P. R. Kannan Rajkumar ¹, P. T. Ravichandran ¹, J. K. Ravi ¹, L. Krishnaraj ¹

Affiliations
1 Department of Civil Engineering, SRM University, Kattankulathur - 603203, Tamil Nadu, IN

Abstract

Background/Objectives: Cement particles disperse due to the flow character of the cement paste which also controls the quality of concrete. Cement particles also disperse due to the addition and action of Super-plasticizers (SPs) and this influences the high fluid paste behaviour. In the development of High Performance Concrete the Super-plasticizers and mineral admixtures such as fly ash plays an important role. SPs are normally adsorbed on the cement particles and sometimes the adsorption will not be even and slightly erratic. This is due to the clinker composition of cement and the type of SP used. Various combinations of materials including mineral admixtures affect the behaviour of the cement–based system and become incompatible like slump loss, delayed setting of concrete etc. Methods: In this study an attempt is made to explore maximum benefits of the compatibility between cement, Fly-ash and super-plasticizers (SP). The Flow table and marsh cone tests were conducted to determine the optimum dosage of the mixture. The different combination was tried in the cement mortar and the improvements in compressive strength were studied. Findings: Results show that the cement with 20% Fly-ash has the better compatibility with Poly carboxylate ether with optimum dosage of 0.9% by weight of cement. Improvement: The investigation shows that the polycarboxylate type superplasticizer has better compatibility with the different types of cement considered in this study.

Keywords

Flyash, Flow Table, Marsh Cone, Poly Carboxylate Ether, Super-Plasticiser.

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L. Krishnaraj ¹, P. T. Ravichandran ¹, P. R. Kannan Rajkumar ¹, P. Keerthy Govind ¹

Affiliations
1 Department of Civil Engineering, SRM University, Kattankulathur - 603203, Tamil Nadu, IN

Abstract

Background/Objectives: The cement industry is seeking ways to reduce the energy resource consumption and environmental load due to cement production. The usage of Supplementary Cementitious Material (SCMs) as a partial replacement of ordinary Portland cement can reduce its environmental load as well as the reduction in construction cost. Methods: In this work it is intended to analyze the mortarcube compressive strength by replacing the cement by 50% of Raw Fly ash and Sieved fly ash, with silica 10, 30% with 12 M Sodium Hydroxide and with and without the addition of lime 10, 30% in one series. Similarly, another set of studied with the ratio of 1:2.5 Sodium Hydroxide 12 M and Sodium Silicate asalkali activators to know the characteristics of the modified mortar. The mortar specimens curedin oven for 24 hrs at 60°c and then left for air curing for predetermined ages at 3, 7, 14, 28 days of curing. The micro structural test was conducted to know their morphological characteristics, particle size and their chemical compositions of cement, Raw fly ash and Sieved fly ash. Findings: Results from the work showed that modified mortar prepared using Sieved fly ashgave 9% increase in compressive strength than RFA. The higher percentage of replacements oflime is observed to increase the strength of Sieved Fly Ash (SFA) mortars. SEM results show that SFA sample taken at different resolution indicate smallest particle size to be 106.4 nm, and EDX results show that reducing the particle size has reduced the carbon content by 10% improved the properties of fly ash. Application/Improvements: Use of sieved fly ash, increases the strength in geopolymer properties is more advantageous in the construction industry for utilizing the fly ash in largequantity and thereby reducing the use of cement content also minimize the CO2 emission during the production in the cement industry.

Keywords

Alkali Activated Mortar, Compressive Strength, Nano Structure Materials, Oven Curing, Sieved Fly Ash

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L. Krishnaraj ¹, P. T. Ravichandran ², P. R. Kannan Rajkumar ²

Affiliations
1 Department of Civil Engineering, SRM University, Kattankulathur - 603203, Tamil Nadu, IN
2 Department of Civil Engineering, SRM University, Kattankulathur - 603203, Tamil Nadu

Abstract

Background/Objectives: Many synthetic additives have been using for improve cement mortar and concrete characteristics, but natural additive is a friendly environment option.In this work, the attempt is made to study, to reduce the pollution from cement production and other materials used in the construction by replacing of Secondary Cementitious Materials. Methods: In this study, the effects of cementitious materials like Ultra-Fine Fly Ash (UFFA) and Nano Silica (NS) on strength development, water permeability of mortar and the optimum use of UFFA and NS in mortars are investigated. Class C Fly Ash which is used as partial replacement of cement was subjected to ball milling for a total duration of 2 hours to obtain UFFA. The NS is a by product obtains from the silicon industries are also used as a replacement material of cement. Cement was partially replaced with four percentages (15%, 30%, 45% and 60%) of UFFA and NS by weight. The specimens used to determine the compressive strength and split tensile strength at the age of 3, 7, 14 and 28 days. Crystallite phase and grain size of UFFA and NS were determined by using X-ray diffraction test and the shape and texture was studied using SEM analysis. Findings: The test results show that strength increases with increase of secondary cementitious materials up to 30% of replacements of cement. Test results indicates that the physical, chemical, mechanical and durability properties of the cement are also enhanced with the influence of the secondary cementitious material. Application/Improvements: Increase in use of fly ash in cement mortar in the construction industry reduces the consumptions of cement as well as the cost of construction.

Keywords

Compressive Strength, Durability Properties, Fly Ash, Micro Structural Study

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