Question

In the laboratory, a paste specimen was prepared using 45 g of water and 100 g of cement then sealed to prevent the loss of water. The paste specimen was cured for 28 days in the constant room temperature. After the 28 days of curing period, a sample from the paste specimen was obtained by breaking off the specimen and the sample was dried in the oven at 105°C for 24 hours. After this oven drying, the sample was then moved to the muffle furnace and burned for 2 hours at 1050°C. The masses of the sample were summarized in the following table. Curing day The original mass of the sample Mass after oven-dry Mass after ignition Sample 28 days 10.962 g 8.947 g 7.560 g Note: Assume that 0.23 g of water is chemically combined with 1 g of cement for the full hydration. Calculate: 1. The amounts of evaporable water per 1 gram of the anhydrous cement? solution: g (3 decimals) (3 marks) 2. The degree (in %) of hydration of paste? solution: % (3 decimals) (4 marks)

Answer 1

Solution: Given that, A paste specimen was prepared using cement cog. of water and 1009.4 C) The amcints o evaporable walor prezi gram the anhydrous coment. Amount qx hlater, w s oligi nase weight –.ovendtlied usight weight evaporable oven dried 10.962-8.947 8.947 2015 8.947 W = 0.22.62 91919 anhydrous comment @1 The degree (tn 7.) o hystration & pasto Deguse of hydration here, wn Weight - ignited weight pgrad wélght - loss on igration Caraten wn 0.23 X100 Duried - Los on 10.962 -7.5600 7:560 3.402 7.560 0.45

2 an 8.947 - 7.560 + 387 = 7:11 0.1950 7.560 -0.45 os 0.1957 Degre og hydratton x 100 0.23 0.84782x100 Degree of hydration 846278. 84.782%