A Review of Current Superplasticizers Highlighting their Specific Properties and Advantages
Johann Plank, Lei Lei
Appears on pages(s):
Superplasticizer, polycarboxylate, phosphate comb polymer, molecular structure, clay tolerance, calcined clay, alkali-activated slag, low carbon binder
Polycarboxylates (PCEs) currently dominate the global superplasticizer market. Among them, HPEG and IPEG PCEs have attained a prominent position as they present the most cost-effective PCEs known at present. Recently, novel vinyl ether PCEs designated as EPEG and GPEG PCEs were introduced, thus broadening the family of VPEG PCEs, and their overall performance is still evaluated. Well documented are now the advantages of novel phosphated comb polymers which can significantly reduce the stickiness of concrete e.g. in UHPC. In spite of many attempts, so far no overall cost-effective clay tolerant superplasticizer has been identified, the challenge being that such a structure must include side chains that however do not contain polyethylene glycol/polypropylene glycol (PEG/PPG) or polyamines. Fortunately, for calcined clay blended cements, HPEG PCEs of specific molecular design as well as zwitterionic (amphoteric) PCEs have proven to be highly effective. Moreover, AAS binder systems were successfully fluidized with APEG or HPEG PCEs exhibiting particularly short side chains (nEO < 10). This review underlines the critical role that innovation in chemical admixtures will play in the future to facilitate a successful migration to low-carbon binders.