Review Preparation and applications of calcium carbonate whisker with a special focus on construction materials Hammad Saulat a , Mingli Cao b,⇑ , Muhammad Masood Khan a , Mehran Khan b,⇑ , Muhammad Mahmood Khan a , Ali Rehman c a State Key Laboratory of Fine Chemicals, School of Chemical Engineering, Dalian University of Technology, Dalian 116024, PR China b School of Civil Engineering, Dalian University of Technology, Dalian 116024, PR China c School of Civil Engineering, Capital University of Science and Technology, Islamabad, Pakistan highlights  Calcium carbonate (CaCO 3 ) whisker is used as efficient filler in many applications.  CaCO 3 whisker helps to reduce the cost of reinforced composites as compared to other fibers.  Different basic preparation methods for the production of CaCO 3 whisker are discussed.  CaCO 3 whisker is effectively utilized in friction materials and reinforcing composite materials.  CaCO 3 whisker is widely used to increase the mechanical properties of cement-based composites. graphical abstract article info Article history: Received 25 September 2019 Received in revised form 10 November 2019 Accepted 12 November 2019 Keywords: Applications Calcium carbonate whisker Whisker preparation Cementitious composites Inorganic filler abstract Calcium carbonate whisker is an emerging class of inorganic fiber having tremendous properties and vast applications. Calcium carbonate whisker is extensively used as a filler due to its tremendous properties including low price, simple preparation requirements and ease of availability. As a filler, it increases the physical and chemical properties such as heat resistance, strength and modulus. Its unique properties are seeking the attention of researchers for utilizing it as a filler in various applications. In this paper, differ- ent basic preparation techniques of calcium carbonate whisker such as metathesis reaction, sol-gel, car- bonation, gravity crystallization and urea hydrolysis are described briefly. In addition to this, the review focus on research advancements achieved in the utilization of calcium carbonate whisker in different applications such as friction materials, paper making, reinforcing composite materials, cement, mortar and concrete. Calcium carbonate whisker is mostly used for enhancing the properties of cementitious materials. In this review, a special emphasis is given to the role of whisker in cementitious materials such as cement, concrete and mortar. Ó 2019 Elsevier Ltd. All rights reserved. https://doi.org/10.1016/j.conbuildmat.2019.117613 0950-0618/Ó 2019 Elsevier Ltd. All rights reserved. ⇑ Corresponding authors. E-mail addresses: minglic@dlut.edu.cn (M. Cao), drmehrankhan@mail.dlut.edu. cn (M. Khan). Construction and Building Materials 236 (2020) 117613 Contents lists available at ScienceDirect Construction and Building Materials journal homepage: www.elsevier.com/locate/conbuildmat