Ruling on stoning the Jamaraat with a piece of concrete

The majority of fuqaha’ stipulated that the Jamaraat
should be stoned with pebbles, which are small stones of whatever type of rock.
Concrete is not rock, so it is not acceptable, according to the majority.

Ibn Qudaamah (may Allah have mercy on him) said: It is
acceptable to stone the Jamaraat with anything that
is called pebbles, which are small stones, whether they are black or white or
red, and whether they are marble, flint, granite and so on. This is the view of
Maalik and ash-Shaafa‘i.
al-Qaadi said: Marble, buraam
and kadhdhaan (types of rock) are not acceptable. And
we may understand from his words that marble and solid stones are not
acceptable either. Abu Haneefah said: It is
permissible to use dried clay or mud, or anything that comes from the earth.
Something similar was stated by ath-Thawri. It was
narrated from Sakeenah bint
al-Husayn that she stoned the Jamarah,
and a man was handing pebbles to her, and she was saying takbeer
with each throw. And she dropped a pebble, so she threw her ring.

We also have a
report that the Prophet (blessings and peace of Allah be upon him) stoned the Jamaraat with pebbles, and he told the people to throw
pebbles the size of chickpeas, so nothing other than pebbles is to be picked
up, and that includes pebbles of all types. It is not permissible to single out
any particular type without evidence, or to add anything else to it, because it
is a topic in which there is no room for analogy.

End quote from al-Mughni, 3/218

In al-Mawsoo‘ah al-Fiqhiyyah (15/277)
it says: When stoning the jamaraat, it is stipulated
that the pebbles be of stone, according to the majority of fuqaha’
(Maalikis, Shaafa‘is and Hanbalis). So it is not permissible to use gold, silver,
iron, lead, wood, clay, seeds, dust, pearls, antimony or plaster in their view,
because the Prophet (blessings and peace of Allah be upon him) threw pebbles
and instructed us to throw pebbles the size of chickpeas, so nothing else
should be picked up. The Shaafaa‘is allowed stoning
the Jamaraat with all kinds of stones.

The Hanafis were of the view that it is permissible to stone
the Jamaraat with all kinds of things that come from
the earth, such as stones, mud and clay, and everything with which it is
permissible to do tayammum, but it is not permissible
to use wood, amber, pearls or gemstones, because they are not from the earth.
End quote.

Based on this,
there is nothing wrong with breaking stones or large rocks and stoning the Jamaraat with them.

As for throwing
concrete or pieces of brick, it is not acceptable according to the majority,
although it is acceptable according to the Hanafis.
However the view of the majority is more on the safe side.

Shaykh Ibn ‘Uthaymeen (may Allah have
mercy on him) was asked: What is the ruling on stoning the Jamaraat
with pieces of concrete?

He replied: Some
scholars think that the stones that are taken from concrete are not acceptable
for stoning the Jamaraat, unless this piece of concrete
contains stone. If it contains stone then there is nothing wrong with it.

End quote from Majmoo‘
Fataawa Ibn ‘Uthaymeen, 23/125

To sum up: If on
the first day you threw pieces of concrete in which there was no stone, then
your stoning was not valid according to the majority, and you have to sacrifice
a sheep, the meat of which is to be distributed among the poor of the Haram; you may delegate someone to do that on your behalf.

If you cannot
afford the price of a sheep, then you do not have to do anything.

And Allah knows best.