## 3 Results and Analysis
### Slump Retention (ASTM C 143-90)  
Fresh concrete loses its workability due to stiffening with time--a well-known phenomenon called \"slump loss\". The consistency changes because chemical and physical factors brought about by early hydration gradually reduce the system's free water and build up the inner skeleton structure. It is well known that the workability of concrete in the concrete industry faces slump loss, which is different for various grades of concrete. Slump loss also varies with time. A study must determine the factors affecting slump loss in the concrete mix. Factors such as cement content, water content, admixtures, weather, and concrete volume influence the workability loss rate. The main objectives of this project are to study the variation of a slump with the time of transportation, which is dependent on the slump value of the concrete mixture. Moreover, slump retention is the most sensitive compared to a well-known slump value because it represents the durability of the concrete mixture for its applications in civil engineering. Slump loss is the rapid stiffening of fresh concrete. Slump loss becomes significant when polymers are used with cement. The stiffening of concrete becomes accelerated under hot climates. This is due to the evaporation of mixing water, hydration of cement, and even water absorption by the aggregates. Retarders lower the rate of hydration of cement. The concrete compressive strength linearly increases with a mixing time of up to 180 min. This increase was 10% after mixing for 180 min [3]. The dispersant remaining in the aqueous phase can influence slump retention. Rapidly adsorbed dispersant from the aqueous phase has a higher rate of slump loss than that was absorbed more slowly from the aqueous phase [7]. The slump loss in the field can be regained by redosing the polymer in the concrete. Besides enhancing the concrete compressive strength, monitoring the slump retention of the fresh concrete modified with water-redicer additives is necessary. In this study, slump retention of the fresh concrete modified with SP62, PC180, and RC897 was monitored when adding water to the mixture and after 30 min of adding water, as summarized in Table 4. The slump of the fresh concrete with and without water-redicer additives was controlled between 200 mm and 220 mm. After 30 min, the concrete modified with water-redicer additives lost its workability (Table 4). Workability loss is affected by cement, water, admixtures, weather, concrete volume, and other factors. The rapid stiffening of fresh concrete is known as slump loss. A hot environment accelerates concrete stiffening due to the evaporation of mixing water, cement hydration, and aggregate water absorption [32]. There were many ways to control the slump loss of fresh concrete. One of the methods was by adding retarder admixture to the mix. By slowing the cement's rate of hydration, retarding admixtures delay the setting. As a result, the water combined with cement decreases due to the decreased hydration rate throughout a particular period. The slump loss in such a mix for a specific period will be significantly lower than that without a retarder [32; 33]. Modifying the concrete with water-redicer additives enhances the concrete compressive strength from 1 day up to 28 days of curing for 3 different contents of cement (300, 350, and 400 kg), as shown in Figures 3-5. For the mixture containing 300 kg of cement at 1 day of curing, the compressive strength was 11.41 MPa, while it was 16.52 MPa and 20.17 MPa for 350 and 400 kg of cement, respectively. Regarding the mixture containing 300 kg of cement, adding 1% of SP62, PC180, and RC897 enhanced the concrete compressive strength by 104%, 150%, and 129%, respectively, as shown in Figure 2. While it was 97%, 141%, and 150%, the mixture contained 350 kg of cement (Figure 3). The growth percentage decreased when the mixture contained 400 kg of cement modified with 1% water-redicer additives (Figure 4).