Yangjaecheon in Late December - Early February

Spring isn't quite here yet. There are icy puddles on the concrete, brittle branches trembling when birds flutter past, off-white leaves of feathery bristlegrass billowing in the wind, the sting on the tip of my nose. 

I've been taking walks along my beloved Yangjaecheon lately. I wanted to share my pictures with you. Some are blurry, some are grainy. I hope they capture the still serenity that I love about the stream - the gem that can only be observed in late winter mornings. 

The familiar scene seen from afar 

Reflected across the small ripples

Mallard ducks - shades of dusty brown, cream, sepia, dark velvet green, and a hint of sandy yellow

Can you guess? Is the sun setting or rising?

Like ice cracking across the surface

Silhouetted against the skies

Crevices in Cracked Concrete

Wow, this is a late post! I'm really sorry for such a delay; I had a terrible cold that drained so much energy out of me. Anyway, this blogpost is  something I've been wanting to write for quite a while! It's a bit different from the previous ones - it's about cracked concrete in winter.


It was early December when I first noticed the cracks in the concrete around school campus. I had just finished school and was on my way to the school gate, when I saw deep cracks at the edges. I pointed them out to my friend, but she didn't think they were that different from before. But I continued to observe the concrete around the manholes, the parking spaces and the school field...the entire campus, which suddenly seemed to crumble away like a falling kingdom. 

As winter progressed, it became clearer: in some areas, the concrete was sinking but in others, the concrete was rising, making huge, uneven crevices through which rainwater and snow fell. It became so bumpy that a bicycle ride through these areas was bound to get a little shakier.

So, what makes concrete crack? I've never seen any concrete road that's completely free of cracks...because all concrete has a tendency to crack. It has a low tensile strength while it has a high compressive strength (the former is only 10% ~ 20% of the latter). Another characteristic - a low thermal expansion coefficient - means that it is not flexible enough to expand or contract according to temperature. That is why the freeze-thaw cycle in the winter is a popular explanation for concrete cracking. With the changes in temperature and humidity, the concrete distends and shrinks, making irregular cracks that are difficult to maintain. 

I recently saw the school maintenance staff walking around the campus, measuring the depth and length of the cracks with a paper ruler. Perhaps they are planning on getting new concrete? It won't be happening any time soon, though; snow and rainfall are still sporadic yet frequent, and a new coat of concrete in such conditions is not going to produce favorable results-!






The next two pictures don't show any cracks but contain the little beauties I saw on other parts of concrete :) 

http://www.angieslist.com/articles/why-concrete-cracks-and-how-prevent-it.htm
http://civil-engg-world.blogspot.kr/2009/04/relation-between-compressive-and.html
http://en.wikipedia.org/wiki/Properties_of_concrete#Cracking