Minfei published in CCR

Published on 4 December 2021 at 12:19

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Express-test in liquid

1 Feb 2023 11:47

Some materials will dry out at the surface when doing nano-indentation tests, even if you do express-tests which only take minutes. This will influence the properties. Today I have been trying to test samples in a liquid. This works perfectly. Sample holders with pool are made out of Lego-blocks.

Meet The Professor

14 Jan 2023 09:34

36 Delft professors took part in "Meet The Professor". We all went to a primary school in Delft to give a lecture to kids in the age 10-12. In total we lectured to about 1000 young students to show them what engineering and science is and to motivate them to join our University in a couple of years.

self-healing Ice-video

21 Dec 2022 17:51

Did you know that Ice is a self-healing materials? In the video you see an Ice sample that is loaded with 6kg weight hanging on a steel wire. The wire slowly cuts through the ice and above the wire the ice sample freezes again.

Self-healing ice

10 Dec 2022 13:46

Make some ice-samples. I made small prisms 40x40x160mm. Attach some weights to a metal wire (copper is even better). Hang the wire over the middle of the sample and magic will happen.

DIC measurements by Shan

6 Dec 2022 14:57

Shan is testing his beams in 4 point bending. The beams have a coverzone made from SHCC containing small fibres and self-healing bacterial agent. He uses DIC to measure crack patterns and crack width.

Shi Xu making capsules

5 Dec 2022 14:55

Today we had a master class given by Amir Tabakovic on how to make capsules for self-healing. Shi Xu can now really boost the capsule production.

Lab-session with MSc-students during Fracture Mechanics course

5 Dec 2022 14:49

In our new MSc-track on Construction Materials we have a unit on Fracture Mechanics. We took the students into the Microlab to perform some fracture tests on notched specimens.

new flexible 4P-bending setup

16 Nov 2022 13:50

Today we tested our newly "in-house" designed 4 point bending setup for small specimens out of brittle, softening or ductile materials. Results look pretty amazing.

3D-printed self healing and strain hardening formwork

19 Oct 2022 17:03

Shan He (Smartincs project) printed the cover layer or (lost) formwork of a concrete beam which is fully loaded with functional properties. Actually this layer will be an essential part of the beams that will be later filled with a reinforcement cage and regular concrete. The printed cover zone contains fibres to provide strain hardening behaviour to ensure small cracks in the structure. Furthermore the material contains self healing agents which will be activated upon cracking and ingress of water, after which they will close the cracks and increase durability of the cover zone and with that of the entire structure. The beams will be tested in the coming months and the self healing ability behaviour will be investigated. Results will be shared later.

Free and restrained autogenous shrinkage in dogbone shaped concrete specimens

19 Oct 2022 16:52

Minfei developed a setup to measure free and restrained autogenous and thermal shrinkage in concrete. The set-up is similar to existing TSTM (Temperature Stress Testing Machine) that are common at many universities. However, the size of our current version is a bit smaller and thus easier to handle and it is positioned vertically to circumvent friction with formwork at early age. The restrained version is build inside a hydraulic universal testing machine (Instron) with allows for fast and active control. In the same machine on the same sample we can do creep and relaxation tests during the hydration of the material. The temperature in the material can be accurately controlled by temperature flow through the moulds (blue tubes in the pictures). Results look very promising and will be shared later.

stiffness mapping

5 Aug 2022 14:23

For our G200 nanoindenter we recently bought the express-test option. Minfei and Shan are trying it out. Left you see a SEM image from a cement paste. Right you see the stiffness maping with the nanoindenter. 10000 indents done within minutes. Looks quite promissing. Size of image is 1x1 mm.

Paper Gao Peng

31 Jul 2022 13:06

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