In case this site is not enough of a resource for you:

• Constructivists quick video
  • https://www.youtube.com/watch?v=dCfSYeBAyZw
• Matholicious (7-12)
  • http://mathalicious.com/
• Mathwire :
  • https://www.youtube.com/watch?v=9GsN5uwLEww
• Making Math matter (K-6)
  • http://makingmathmatteronline.com/#
• Mathematics Educations
  • http://mathforum.org/mathed/constructivism.html
• Constructivsism in the Classroom
  • http://www.teach-nology.com/currenttrends/constructivism/classroom_applications/
• Math for teens in constructivist
  • https://tapintoteenminds.com/