Lightweight aggregate concrete may be more influenced by the Hence, effects of aggregate properties on concrete properties is huge.

endstream endobj 860 0 obj <>stream h�4ѽJ1��[�;�d�_�6�6"vb!��� h�d˱ This factor is of secondary importance. 2. Rough-textured and elongated particles require more cement paste to produce workable concrete mixtures, thus increasing the cost. It was also found that compressive strength has no … Different When the particles are of uniform size the spacing is the greatest, but when a range of sizes is used the void spaces are filled and the paste requirement is lowered. Grading of aggregates depends on the proportions of coarse and fine aggregate. On the other hand in smaller size aggregates the surface area is increased which increases w/c ratio and lower strength is achieved.

It also effects pumpability, and durability of concrete. Well graded aggregates result in the least amount of voids in a given volume. Concrete strength is fairly independent of aggregate size.

�>�� At a given water ratio, within the range employed in most structural concrete, smaller maximum sizes of aggregate will tend to produce higher concrete strengths than larger ones. This established the importance of ensuring that the right aggregate size is used in the production of concrete. for 1+3, enter 4.

Strength of concrete is also affected by the properties of coarse aggregates besides water-cement ratio and other properties. Solve this simple math problem and enter the result. If you get concrete and sieve out the coarse aggregate, the strength of standard cylinders does not change much. Stay informed - subscribe to our newsletter.

Undesired properties of coarse aggregate may affect the strength, durability, and performance of concrete negatively.
Variation in the size of Aggregates changes the water demand, cement content, micro-cracking (strength) in concrete.

�޽2�;M^H�����\�r:�w_�ϟe������l��_?.}? Most fine aggregate is often in the wet state with surface moisture up to five percent. increase in aggregate size results in a decrease in the compressive strength of concrete. If grading of aggregate is varied, it also changes cement paste content (cost economy), workability of the mix,

Less voids result in excessive paste availability in a unit volume and more lubrication. The more these voids are filled, the less workable the concrete becomes, therefore, a compromise between workability and economy is necessary.Effects of aggregate properties on Concrete like Grading of aggregates depends on the proportions of coarse and fine aggregate. When determining the strength of normal concrete, most concrete aggregates are several times stronger than the other components in concrete and therefore not a factor in the strength of normal strength concrete.

In any case, the strength is not contingent upon having coarse aggregate particles touching as so many seem to think. 859 0 obj <>stream

The larger sizes will require less mixing water and hence, for a given cement factor, will produce concrete of lower water-ratio than the smaller sizes.
These different properties of aggregate allow designers and contractors the flexibility to meet their design and construction requirements as well as manage costs of the concrete effectively. Hence the mix is cohesive and avoids segregation.Surface texture of aggregates itself depends on rock hardness, grain size, porosity, previous exposure and affects workability, paste demand, initial strength of concrete. If grading of aggregate is varied, it also changes cement paste content (cost economy), workability of the mix, density and porosity.It is an important factor and has a maximum influence on workability. Cook (1989) showed that, for compressive strengths in excess of 69 MPa (10,000 psi), smaller sized coarse aggregate produces higher strengths for a given water-to-cement The moisture content can range from less than one percent in gravel to up to 40 percent in very porous sandstone and expanded shale. Round smooth aggregates require less water and less lubrication and greater workability in a given w/c ratio.Coarse aggregate makes up about 75% of concrete by volume.

The lower the water to cement ratio, the more the effect of coarse aggregates on the strength of concrete. E.g. In large size aggregates surface area to be wetted per unit weight is less, and the water cement ratio is less which increases the strength. In general for strength upto 200 kg/cm 2 aggregates upto 40 mm may be used and for strength above 300 kg/cm 2 aggregate upto …

�0 �_��dP�R���`u+B��%� B1r$�ߡХ�{�� Bו#{�pL6z1�R�� �X�6�:C��W���|��"�9������.������aX9,6aAEƞ�a�gL���Ӗ���� �*b Q.: How much stronger is a floor made with 1/2-inch aggregate than one with 3/4-inch aggregate if all other ingredients remain the same? 3.

}?K7��RBJH ))%����RRJJIR��!eJ�R�1#5fj�$��Ѡ��֩S������/�/���s��+��+��7��ěx�X"[l����&o�:-�ިѤx�gx��x��x�x�x��x�Wx�Wxo� ��{/����e}x}�\��? h��[]�\��+�f�����`�C�P�0&(�b��Hp�}�G��3���C�w�d�;��O��S�]ݽ�RK+R{��c�(6��ZF�e�����I��fi*���O���F���S-J�*�R�Q�|a��Q��&E{ޒ�W�[�(:Kw�%/���3�[���D+ފ���#ӊ�f�,j����|Dk���ܴd�m/C��je�#=3Fq-3_9��[k>?��Ă�ﴅ.���n��m>�`�)��֤��H�G]���e�&_�k��Ж/�(����2�H��e�����;Nj닞J����O4�;ZM�6룖�X��i��%Ȗ�� ��4�}^WҦm�Nz�|y���-����iql�z���KZ�E>�u�o�ղ4�rP�l�}��ߚNh��=3��y�j���o�6�'��Ӆɇ This surface moisture on the fine aggregate creates a thick film over the surface of the particles pushing them apart and increasing the apparent volume. A.: If the quantities of coarse aggregate, fine aggregate, cement and water are the same for both mixes, the mix with l l/2-inch aggregate will have greater slump and will probably bleed more. In fact, most of the properties exhibited by concrete are what it is made up of - aggregates.Let us know in the comments what you think about the concepts in this article! Angular aggregates increases flakiness or elongation thus reduces workability. Compressive strength of concrete increases up to the maximum aggregate size of 1.5 inch. The concrete made from the 9.5 mm, 13.2 mm and 19.0 mm aggregate sizes had workability (slumps) of 10 mm, 13.5 mm and 20 mm, respectively. endstream endobj 861 0 obj <>stream %PDF-1.7 %����

The compressive aggregate strength is an important factor in the selection of aggregate. When determining the strength of normal concrete, most concrete aggregates are several times stronger than the other components in concrete and therefore not a factor in the strength of normal strength concrete.