Influence of Chloroprene Rubber Latex on Set Times and Early Hydration of Cement
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RESEARCH ARTICLE-CIVIL ENGINEERING
Influence of Chloroprene Rubber Latex on Set Times and Early Hydration of Cement Izhar Ahmad1 · Kashif Ali Khan2
· Tahir Ahmad3
Received: 12 November 2019 / Accepted: 1 April 2020 © King Fahd University of Petroleum & Minerals 2020
Abstract This study was carried out in order to investigate retardation time of chloroprene rubber (CR) latex on the cementitious system in relation to its effect on the heat of hydration of cementitious system. Set times, consistency and heat evolution tests were carried out on ordinary Portland cement (OPC). Three different curing environments were selected with different CR to cement ratio i.e., 0%, 5%, 10%, 15% and 20%. The data revealed that consistency was increased under high temperature and low relative humidity for cement pastes. While achieving standard consistency, water required by the controlled specimen was reduced by 43% with the addition of 20% CR latex. Regarding heat of hydration, it was found that heat of hydration of latex-modified cement pastes was higher than the controlled cement paste after 48 h. Keywords Cement · Chloroprene rubber latex · Fineness · Consistency · Set times · Heat of hydration
1 Introduction In hot temperate areas, due to harsh temperature conditions, there occur various problems during the concrete pouring and finishing operations like rapidness in the hydration of cement as well as in the rate of moisture loss from the green concrete surface. Besides, stiffening occurs very fast in the fresh cement paste or freshly placed concrete and also substantial amount of loss in the slump comparatively to the same mixes placed under normal temperature conditions [1, 2]. High temperature fasten the rate of cement hydration reaction that leads to prior setting of concrete due to which the mixture becomes stiff in a short interval of time [3]. Due to
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Kashif Ali Khan [email protected]; [email protected] Izhar Ahmad [email protected]
1
Department of Civil Engineering, Imperial College of Business Studies Lahore, Shahkam Chowk, Bahria Town, Lahore, Pakistan
2
Department of Civil Engineering, CECOS University of IT & Emerging Sciences, Sector F 5 Phase 6 Hayatabad, Peshawar, Khyber Pakhtunkhwa 25000, Pakistan
3
Department of Civil Engineering, Sarhad University of Science and Information Technology, Landi Akhun Ahmad, Hayatabad Link Peshawar Ring Rd, Garhi Sikandar Khan, Peshawar, Khyber Pakhtunkhwa 25000, Pakistan
high temperature, loss of moisture occurs from the surface of the freshly placed concrete which leads to slump loss and shrinkage cracks appearance on the surface. Therefore, it is recommended that setting of cement should be according to the prevalent conditions of the environment which means that setting phenomenon should be not very early neither delayed because initial and final set times almost reduced to half as compared to the setting phenomenon occurring at normal room temperature when the temperature is raised from 27 to 45 °C [4]. Under standard normal laboratory conditions whet
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