Eliminating the Shrinkage of High Strength Concrete by using Super Absorbent Polymer (SAP)

Abstract

High Strength Concrete (HSC) is one of the  most popular types of concrete used in the world. This type of concrete has a low rapid  hydration of cementation materials with low  w/cm and the external surrounding  environment condition exposed the HSC to  high autogenous shrinkage. If this shrinkage is  not treated well that well led to cracking, in  this case HSC need to convenient curing  necessary at the earliest time. This study  presents the use of Super Absorbent Polymer  (SAP) as internal curing agent to eliminate  shrinkage. Two types of shrinkage are tested in  this study (Autogenous shrinkage and drying  shrinkage).  Two groups of concrete mixes(A and B) are  studied in this study each group have five types  of concrete mixes, four mixes with high and  ultra-high compressive strength (RPC, MRPC, HSC and SCC) and the last one with normal  compressive strength (NSC). Group A  represent concrete mixes without SAP addition  and group B for concrete mixes with SAP.  SAP was added for all mixes at 0.3% by  weight of cement and adding 20ml water for  each gram of SAP, specimens with dimensions  (40*40*160) mm were used for testing  shrinkage for each mix with and without SAP,  average values for two specimens was taken as  a results. It was found that concrete mixes of  group B have lower shrinkage than the  shrinkage of concrete mixes in group A at 28  days age with reduction of autogenous  shrinkage(AS) of (57%, 35%, 37%, 44.5% and  37.5%) respectively and for drying shrinkage  the percentage of reduction was (89.5%, 72%,  82%, 70% and 71%) respectively, addition of  SAP to concrete mixes proves to have active  effect in reducing the shrinkage of concrete.