Question

answer all Q with clear writing pls

8) Putting the right amounts of cement, aggregate and sand together is pretty important, what is an accepted ratios of those by weight? Cement _ _ Sand Aggregate 9) What is the general range for acceptable ratio of Water to Cement? percent. (give the range and what is an absolute minimum?) hint this was on one of the good readable slides in the crappy PDF. 10) When the water to concrete ( W/C) ratio increases, the strength of the cured concrete does what? circle the correct one)

Answer 1

Let's assume that we using mis assume that we are concrete. The nominal mix for mi5 concrete is 1:2:4 now. volume uk derece • Volume of dry concrete = 0.54 to 1.57) x volume of wet concrete To find cement for 1: 2:4 = A *.54) -0.22 m2 tendono (1+2+4) Now multiply it with density of concrete $ 0.22x 1400 = 3168 kg Density of rement & 1400k/ - To find sand for 1: 2 4 2 x 1.54 = 0.44 m (1+2+4) Now, multiply with density of sand (beneity of 30-44*1700 - 748 kg sand 2 1900 kg/m] - to find coarn aggregate for 1: 2:4 € 4 x 1.54 =0.88 m² (1+2+4) Now, multiply it with density of coarse aggregate coarse a O. 88 x 1650 = 1452 kg Density of (ber aggregate 1650 Now the weight ratio of cement: sand coarse aggregate is 3168:748:1452 1 2 :36:4.5%

- Similarly we calculate the weight ratio's for m2o and M2s. There is no fitted ratio The acceptable ratio of weights elepends on arade of concrete 1 concrete hardens as a result of the chemical reaction to between cement and water. For every kilogram of cement about 0.35 kilogram of water is needed to fully complete hydration reactions. However, a mix with a ratio of 0.35 may not min thoroughly I may not well enough to be placed. more water is therefore used than is technically necessary to react with cement. water cement ratios of 0.45 to 0.6 are more typically used 10 The water to cement ratio affects two properties: strength and workability of concrete. Once this ratio increases, the compressive strength decreases and the wordability rises. so, to provide both good strength and workability of the concrete we could add additives such as plasticizer and so on instead of increasing the ratio.