Effects Of Polymer On Properties Of Cement-based Composite

The influence of polymers of different properties and structures on the compressivestrength and bending strength of polymer cement -based composite was studied. The resultof macro-and micro-examination is stated that the properties of polymer modified mortarswere obviously better than that of unmodified mortars. An increasing polymer-cement ratioleads to rapid decrease of the compressive strength and a slow increase of the bendingstrength of the modified mortars. The mechanics capability of material is strengthen withthe glass temperature raised. When the glass temperature reach the hightest temperature,then the mechanics capability begin to decrease. The mechanics capability ofalkalinepolymers modified cement mortars is higher than the others'. And polymers possessed a lotof reaction function groups(-COO^-,-COOR,-OH) have bigger reforming effectingon the mechanics capability.Infrared spectroscopy observations show that polymers participated in the cementhydration and there was chemical reaction between polymers and hydration product in thecement.SEM observations show that there are a lot of holes and stomas in the Porlantcement. And cement mortar is not dense. Polymer fills in the big holes and forms thepolymer film with felting properties, which packages water and cement. So it's feltingstrength is increased and the properties of mortar is improved. The X-ray diffractionobservations show that polymer makes cement hydration slowly and the compressivestrength decreased. With hydrating, the consumption amount of Ca(OH)₂, C-S-H and AFtare increase continuously. They came into being strong and weak contact point, whichmade the net microstructure strong and bending strength increased.Sum up, when pH of polymers was alkaline and polymers possessed a lot of reactionfunction groups and glass temperature 1.7℃, the polymer modified cement -basedcomposite had the best mechanical properties.This dissertation brings forth new ideas. It searches the common laws from thefunctional groups,the glass temperature and pH of polymers. And offers the theoreticsgist; and provides direction for increasing wear and decreasing cost of composite materials.