Raw data and supplementary material of the second inter-laboratory testing program (RRT2, self-healing concrete with MgO-based expansive minerals) of the EU COST action SARCOS

This data is the result of a collaboration of scientists working on the development of self-healing concrete within the framework of the European Cooperation in Science and Technology (COST) Action “Self-healing as preventive repair of concrete structures” SARCOS CA15202.

In the framework of SARCOS 6 inter-laboratory testing programs are being executed to investigate possible standard test methods for self-healing concrete, each of the testing programs focusing on a different self-healing technique:
(1) Concrete with mineral additions,
(2) Concrete with the addition of magnesium oxide,
(3) Concrete enhanced with crystalline admixtures,
(4) High performance fibre reinforced concrete enhanced with crystalline admixtures,
(5) Concrete with preplaced macrocapsules containing polymeric healing agent, and
(6) Concrete with encapsulated bacteria.

The data which can be found here have been obtained in the inter-laboratory testing program 2. In total, 9 labs from seven different European countries participated in this inter-laboratory test: University of Cambridge (UK), Cardiff University (UK), Politecnico di Torino (Italy), Institute for Construction Sciences Eduardo Torroja (IETCC-CSIC) (Spain), University of Córdoba (Spain), Kaunas University of Technology (Lithuania), Riga Technical University (Latvia), Cracow University of Technology (Poland), National Centre for Scientific Research “Demokritos” -NCSRD (Greece). All specimens were cast at Riga Technical University and were then distributed to different labs, where they were tested. 

The methodology used is based on water permeability tests, water capillary absorption tests, and crack width measurements, comparing their performance to evaluate self-healing. The inter-laboratory test was split up in two parts. Fibre-reinforced concrete prisms with and without mineral additions were cracked in a three-point bending test with a passive crack-width control and studied in a capillary water absorption test. Concurrently, fibre-reinforced concrete discs with and without mineral additions were cracked using a splitting test-setup able to produce tensile cracks, and subsequently exposed to water permeability test to evaluate the water flow going through the cracks. After initial pre-cracking, all the samples were stored submerged in water to promote the self-healing reactions during three predefined periods of 1, 3 and 6 months. The same samples were tested before healing, and at the above-mentioned three monitoring periods to monitor the healing process. Crack widths were observed through optical microscopy and the crack mouth healing calculated thereafter. A final complementary test was also done to assess the durability of the cracked and self-healed specimens through chloride ingress tests.