PORTLAND CEMENT - Materials for Civil and Construction Engineers - page 234

admixture after 28 days of curing. The compressive strengths of cubes
in psi with and without admixture are shown in Table P6.29.

Table P6.29

Compressive strength, psi

Cube No. With admixture Without admixture

1 3520 3550

2 3645 3785

3 3715 3720

4 3500 3645

5 3414 3560

6 3685 3645

7 3545 3400

8 3515 3555

Using the statistical t -test, is there a significant difference between
the means of the compressive strengths of the two cement mortars at
a level of significance of 0.10?

6.12 References

American Concrete Institute. Building Code Requirements for Reinforced
Concrete . ACI Committee 318 Report, ACI 318-99. Farmington Hills,
MI: American Concrete Institute, 1999.
Borger, J., R.L. Carrasquillo, and D.W. Fowler. “Use of Recycled Wash
Water and Returned Plastic Concrete in the Production of Fresh
Concrete.” Advanced Cement Based Materials , Nov. 1 (6), 1994.
Chini, S.A. and W.J. Mbwambo. “Environmentally Friendly Solutions for
the Disposal of Concrete Wash Water from Ready Mixed Concrete Op-
erations.” Proceedings, Beijing International Conference . Beijing, 1996.
Hewlett, P. C. Concrete Admixtures: Use and Applications . Rixom, M.R., ed.
Lancaster, UK: The Construction Press, 1978.
Hover, K. and R. E. Phillco. Highway Materials Engineering, Concrete . Pub-
lication No. FHWA-H1-90-009, NHI Course No. 13123. Washington,
D.C.: Federal Highway Administration, 1990.
Kosmatka, S.H. and W.C. Panarese. Design and Control of Concrete Struc-
tures . 13th ed. Skokie, IL: Portland Cement Association, 1988.
Kosmatka, S. H., B. Kerkhoff and W. C. Panarese. Design and Control of Con-
crete Mixtures . 14th ed. Skokie, IL: Portland Cement Association, 2002.
Mehta, P. K. and P. J. M. Monteiro. Concrete Structure, Properties, and
Materials . 2d ed. Upper Saddle River, NJ: Prentice Hall, 1993.
Neville, A. M. Properties of Concrete . 3d ed. London: Pitman Books Ltd,
1981.