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A method for assessing bond performance of cement-based repair materials Jueshi Qian a,⇑, Chao You a, Qingzhen Wang a, Hongtao Wang b, Xingwen Jia a a b
College of Materials Science and Engineering, Chongqing University, Chongqing 400045, PR China
Department of Chemistry and Materials, Logistical Engineering University, Chongqing 401311, PR China
h i g h l i g h t s
We proposed a method to test bond performance for cement-based repair materials.
A specimen of circular concrete plate with a frustum hole in the center was designed.
Three cement-based repair materials with different shrinkage were compared.
Appearance, permeability and bond strength were tested on the same specimen.
This method can reﬂect the effect of repair material shrinkage on bond performance.
a r t i c l e
i n f o
Received 12 January 2014
Received in revised form 4 May 2014
Accepted 29 June 2014
Available online 19 July 2014
a b s t r a c t
A test method is proposed to assess bond performance of cement-based repair materials in this paper. A specimen of circular substrate concrete plate with a frustum hole in the center was designed ﬁrstly, then the repair material was cast into the hole in a certain height, and lastly, the bond performance was assessed by checking the bond appearance, and testing the permeability and bond strength of the interface. Portland cement (PC), sulphoaluminate cement (SAC) and magnesium phosphate cement (MPC) mortars were used as repair materials to assess the bond performance by means of proposed method and the existing bending method. The results show that for PC and SAC mortars, a lot of thick cracks occurred on the interface due to the high shrinkage, while no crack was found in MPC mortar with lower shrinkage when proposed method used. For PC and SAC mortars, proposed method obtained lower bond strength than the bending method, which did not reﬂect the shrinkage of repair materials on the interface. It can be concluded that proposed method is suitable for assessing the performance of cement-based materials because it can measure the effect of repair material shrinkage on the bond of interface.
Ó 2014 Elsevier Ltd. All rights reserved.
Concrete is one of structure materials widely used in the world, and however may deteriorate and is even damaged due to the impact of the surrounding environment during the service term.
The deteriorated or damaged concrete must be removed, and replaced with new concrete or repair materials. On the other hand, concrete structures may be designated to carry more load, therefore, it should be strengthened. It is usual to increase the cross-sectional area of the structure by attaching a new layer of concrete or repair material to the substrate concrete.
High-performance repair material is essential to the repair work. Current research works on the repair materials can be
⇑ Corresponding author.
E-mail addresses: firstname.lastname@example.org, email@example.com (J. Qian). http://dx.doi.org/10.1016/j.conbuildmat.2014.06.048 0950-0618/Ó 2014 Elsevier Ltd. All rights reserved.
divided into two aspects: to focus on developing new kinds of repair materials and improving the existing repair materials, and to develop new assessment methods. These works are expected to pick out some high-performance repair materials or evaluate accurately the behavior of repair materials in practical repair engineering. In recent years, there have been many new repair materials to be developed for repairing and rehabilitation of concrete structures
[1,2], which can still be classiﬁed into three kinds: cement-based materials, polymer modiﬁed