## 2 Materials and Methods  
### Concrete Mix Designs and Mixing Procedures  
Four different concretes were used in this study, the base concrete used for the original girders and continuity joints and the three specialty concretes used for repair. The test girders and the continuity joints were constructed of a Class AA concrete, which was the specified concrete for bridge superstructures outlined in the Oklahoma Department of Transportation (ODOT) standard specifications [29]. The mix design is shown in Table 1. The material was provided by the ready-mixed concrete provider Dolese Bros. Co. in Norman, OK. The material was loaded into a standard mixer truck and the transit time between the batch plant and the casting location was approximately twenty minutes. Water was added upon arrival of the truck to obtain the desired slump before being placed in the forms.  
The first repair material evaluated was the UHPC. The mix design is also shown in Table 1. A 0.15 m\({}^{3}\) batch of UHPC was mixed in a Mixer Systems, Inc. Horizontal Shaft Mixer with a 0.6 m\({}^{3}\) capacity. First, all the dried materials were placed in the mixer and allowed to blend for ten minutes. Then, half of the water reducer was added to the water, and the water then added to the mixer over the course of two minutes. After an additional minute of mixing, the remainder of the water reducer was added. Once the mix achieved flowability, the fibers were added to the mixer and allowed to blend over the course of three minutes. The material was then dispensed into buckets for placement into forms.  
The second repair material evaluated was the FRSCC. The mix design is also shown in Table 1. The same mixer was used for the FRSCC as the UHPC and the same amount of concrete was mixed. After adding the air entraining admixture to the sand, all the aggregates were added to the mixer with half of the water and allowed to mix for several minutes. Then, the cementitious material was added to the mixer, along with the high range water reducer and the remaining water. After mixing for eight minutes, MasterFiber MAC Matrix polypropylene fibers were added to the mix and allowed to disperse for three minutes. Citric acid was added to the mixture at a dose of 0.4% of the weight of the Type K shrinkage compensating additive alongside the fibers to provide additional working time, due to the fast-setting nature of the mixture. The material was then dispensed into buckets and placed in the forms.  
The final repair material evaluated was the MALP concrete. This proprietary product consisted of a dry, bagged mixture containing the cementitious material, aggregates, and 25 mm long fibers, along with a liquid activator. The manufacturer's recommended proportions for mixing was one bag of dry material to one container of activator. The material was mixed according to the manufacturer's recommendations in 0.02 m\({}^{3}\) buckets using the supplied mixing paddle attached to a standard electric drill. The liquid activator was poured into the bucket, and the dry ingredients were then slowly poured on the liquid activator while the paddle was simultaneously rotating in the bucket. The materials were mixed for one minute before being poured into the forms. The material was only mixed one bucket at a time, and subsequently poured over the previous material, due to its fast-setting nature. Due to the speed of mixing and placement, no cold joints were apparent upon removal of the forms.