More images on 3 different samples

Work in progress. Here is crack development for 3 different samples based on different loading conditions, various aggregate size and agg/paste ratio.

Currently working on quantification of damage obtained from simulations. Regarding our previous post these are attempts to understand the crack formation mechanism (and hopefully fitting on a timeline).

SIMULATION: Crack formation under Aggregate Expansion

We have been trying to run simulations on various loading conditions and material properties to investigate crack formation in 2D sections. While we are busy with sample analyses and running simulations, here is a taster (if you may call it a result) video of how cracks grow under expanding aggregates. This simulation is based on a real test specimen (Upside down though).

Simulations continue till the specimen fails (or reaches a predefined stain level). You may realise some simplification on the section identification. Here are how the original sections look like. These specimens have been kept in 60°C reactor (RH 100%) for 20 weeks before sample preparation process.

 1- Normal Light Image

2- UV Light Image

Specimens are based on original mix design of Nautesund Bridge. you can find more information about this testing campaign here.

I have also done damage rating index analyses on this (and various other) specimens based on method defined by Grattan-bellew (1992). Some results regarding These analysis are as follows:

 Damage rating index - calculated based on Grattan Bellew (1992)

Distribution of Crack types observed on our samples

DRI analyses and simulations are continuing in full speed. Soon I will provide more data (and definitely more results) on our blog.

Busy months ahead..

FRAMCOS - 8: Call for Papers

 

8th International Conference on Fracture Mechanics of Concrete and Concrete Structures will be held in Toledo Spain, March 2013. Deadline for Paper submission is 15 September, approaching.

Hopefully we will be there to present our findings.

PAT-ASR team in ICCRRR, Cape Town

It is almost time for yet another big conference on concrete research. We are participating in 3rd International Conference on Concrete Repair Rehabilitation and Retrofitting in Cape Town, South Africa. We are presenting two papers in this conference. It will exciting to meet and interact with colleagues around the world.

It's a long flight with an exciting ending. Looking forward to it.

Mechanical Properties Degradation due to ASR-Swelling: Trial Tests 1

Our experimental campaign is becoming larger! We decided to have look also to the degradation of the mechanical properties due to ASR-swelling. 

We will store the specimens in homemade reactors which ensure a temperature of 38C and RH>95%.

Homemade reactors.

The specimens will be tested for Young's modulus and splitting tensile strength.

Just to get familiar with the type of test and the test machines, we had a trail cast at the middle of June and that week we performed the experiments.

Here there are some pictures of the tests.

Preparation specimens for the Young's Modulus test.

Disposition of LDVT for the Young's Modulus test.

Young's Modulus test.

Splitting tensile test.

Crack pattern after splitting tensile test.

Crack pattern after splitting tensile test.