The Effect of Water to Cement Ratio on Early Age Properties of Cement Paste and Mortar by UPV Mohit Gupta Dept. of Civil Engineering BRCM College Bahal, Haryana (INDIA) Dr. Arabinda Sharma Dept. of Civil Engineering Associate Professor, BRCM College Bahal, Haryana (INDIA) Abstract - The research work done through an experimental investigation carried out to study the effect water to cement ratio on early age properties of cement paste and mortar are investigated using an ultrasonic pulse velocity method. Properties that are difficult to determine to the early age performance of these are tested, including setting and hardening time, strength development and compressional wave (P-wave) arrival. Measurements of these properties using an ordinary Portland cement (OPC) are presented for cement paste having water to cement ratio 0.40 and 0.45. These properties were also measured for mortar having water to cement ratios (0.40, 0.45 and 0.50). Early age setting time behaviours of cement pastes and mortar are contrasted. It was found that while increasing the water to cement ratio ultrasonic pulse velocity decreases at early age. Key words: Ultrasonic Monitoring, Setting,Strength Development, Prolonged Agitation INTRODUCTION: The development of microstructure in a cementitious material matrix evolves occurs during the setting process due to the ongoing hydration occurring in the cement paste and mortar. When cement paste and mortar transforms from suspension to solid mode the strength parameters change with time. The evolution of microstructure as a result of hydration reduces the porosity and increases the strength. This change is relatively rapid during the first day of hydration and slows down over time. The ultrasonic method can be used to follow setting. The change of ultrasonic velocity over time is sensitive to the differences in setting behaviour of the tested mixtures. Initial setting seems to correspond with the point of inflection of the velocity-vs.-time graph and final setting time with point at which the velocity becomes constant. Methodology: Continuous monitoring of setting and hardening process was performed using two cement paste mixtures of water to cement ratios (w/c=0.40 and w/c =0.45) and three mortar mixtures of water to cement ratios (w/c=0.40, w/c=0.45 and w/c=0.50). Also effect of sand to cement ratios (s/c=0.25, s/c=0.50 and s/c=3) on setting and hardening in mortar keeping water to cement ratio constant (w/c=0.50) was studied. LITERATURE REVIEW: United States researcher Dr. Floyd Firestone first applied this method in 1940. After two years the applicability of the instrument used for the method was validated and it was titled as ‘Flow detecting device and measuring instrument’. The device was then used by many researchers for measuring the presence of inhomogeneity in density and elasticity of concrete materials. James F. McNulty (1966) performed this test on using piezoelectric transducers and named it as ‘Ultrasonic testing apparatus and Method’. According to him, the crystals vibrates at ultrasonic frequencies and the wave is transmitted to the object being studied through a mechanical coupling. Reinhardt (2004) developed test setup for the exact determination of transmitted ultrasonic pulse. It was shown that the good estimate of initial setting time can be determined from the velocity vs. age of cement paste by mathematical procedure and final setting time can be determines using empirical experience relationships. Vol. 5 Issue 05, May-2016 International Journal of Engineering Research & Technology (IJERT) ISSN: 2278-0181 http://www.ijert.org IJERTV5IS050698 (This work is licensed under a Creative Commons Attribution 4.0 International License.) Published by : 550
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The Effect of Water to Cement Ratio on Early Age Properties ......Early Age Monitoring of Cement Paste using Ultrasonic Test Figure 1 Schematic representation of typical evolution
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The Effect of Water to Cement Ratio on Early
Age Properties of Cement Paste and Mortar by
UPV
Mohit Gupta Dept. of Civil Engineering
BRCM College Bahal,
Haryana (INDIA)
Dr. Arabinda Sharma Dept. of Civil Engineering
Associate Professor,
BRCM College Bahal,
Haryana (INDIA)
Abstract - The research work done through an experimental
investigation carried out to study the effect water to cement
ratio on early age properties of cement paste and mortar are
investigated using an ultrasonic pulse velocity method.
Properties that are difficult to determine to the early age
performance of these are tested, including setting and
hardening time, strength development and compressional
wave (P-wave) arrival. Measurements of these properties
using an ordinary Portland cement (OPC) are presented for
cement paste having water to cement ratio 0.40 and 0.45.
These properties were also measured for mortar having water
to cement ratios (0.40, 0.45 and 0.50). Early age setting time
behaviours of cement pastes and mortar are contrasted. It
was found that while increasing the water to cement ratio