Thanks for contacting Ask Extension with your question about weeds in your lawn.  I can not ID the weeds by the pictures that you provided.  I think it may be tall fescue, in which case there is no herbicide that will kill it without killing the surrounding grass. If the infestation is small, you can dig the grass clumps out with a shovel, just ensure that the entire crown and top few inches of roots are removed. You can then add soil and replant the desired grass from seed. If the infestation is larger, use a nonselective herbicide such as glyphosate to kill the grass (e.g., Roundup Weed and Grass Killer, though there are many others). Keep in mind this will kill the lawn grass too, so take care to spray as little as possible.
     Tall fescue (Schedonorus phoenix [Scop.]) is a cool season perennial so it is actively growing now. This clump forming grass typically appears as a circular patch that can become wider from tillering. Short rhizomes (underground runners) may be present. The leaf blades are fairly wide. When tall fescue gets mixed in with a slower growing, finer textured turfgrass species, it becomes quite noticeable. Mowing can help to even out the height difference, however tall fescue's lower stems are often lighter colored, allowing for the spots to remain noticeable. The leaves are dark green in color and the lower surface is glossy. 
I'm attaching a link to a publication from the university of Michigan about ID and control of Tall Fescue. It has close up pictures of Tall Fescue that you can use to ID the grass, or you could dig up the grass, including the roots and take it to the Master Gardener Help Desk for identification. The help desk is located at the extension office: Sunset Building, room 107, 4077 research way, Corvallis OR 9333

 Hope this helps.