Moderate-heat portland cement and Anti-cracking of large-area concrete
Moderate-heat portland cement and Anti-cracking of large-area concrete
Key words
Moderate-heat portland cement, low-heat portland cement, large-area concrete, concrete cracking, anti-cracking agent
Moderate-heat portland cement, (also low-heat portland cement) refers to a hydraulic cementitious material with moderate heat of hydration made from Portland cement clinker of appropriate composition, adding appropriate amount of gypsum, and grinding it. It is called medium heat Portland cement, or medium heat cement for short. .
Low-heat portland cement is one of the commonly used dam cements. Moderate-heat portland cement has the advantages of low heat of hydration, strong sulfate resistance, low dry shrinkage, and good wear resistance.
Moderate-heat portland cement has the characteristics of low hydration heat and high MgO content. The early exothermic heat is lower and the exothermic rate is slower, and the MgO in the medium-heat Portland cement will slowly hydrate to produce Mg(OH)2 and cause volume expansion in the later stage. It can effectively compensate the volume shrinkage of large-area concrete in the later cooling stage.
Cement concrete releases a lot of heat during the hydration and hardening process, and the resulting temperature stress is the main cause of concrete cracks. In order to prevent cracking in mass concrete projects, the selection of medium-heat Portland cement, fly ash, silica fume, superplasticizer and high range anti-cracking agent can effectively avoid large-area concrete cracking.
