1. The pozzolanic reaction is the chemical reaction that occurs in portland cement upon the addition of pozzolans. It is the main reaction involved in the Roman concrete invented in Ancient Rome and used to build, for example, the Pantheon. The pozzolanic reaction converts a silica-rich precursor with no cementing properties, to a calcium silicate, with good cementing properties. In chemical terms, the pozzolanic reaction occurs between calcium hydroxide, also known as portlandite (Ca(OH)2), and silicic acid (written as H4SiO4 or as Si(OH)4): Ca(OH)2 + H4SiO4 CaH2SiO4·2 H2O or summarized in abbreviated notation of cement chemists: CH + SH C-S-H The product CaH2SiO4·2 H2O is a calcium silicate hydrate, also abbreviated as C-S-H in cement chemist notation, the hyphenation denotes the variable stoichiometry. The ratio Ca/Si, or C/S, and the number of water molecules can vary and the above-mentioned stoichiometry may differ. Many pozzolans may also contain aluminate, or Al(OH)4, that will react with calcium hydroxide and water to form calcium aluminate hydrates such as C4AH13, C3AH6 or hydrogarnet, or in combination with silica C2ASH8 or strätlingite (cement chemist notation). In the presence of anionic groups such as sulphate, carbonate or chloride, AFm phases and AFt or ettringite phases can form. slag reaction The reaction of slag in cement with and without interaction with the clinker hydration is extensively discussed in previous works of the current authors (/4/,/5/) and is briefly reviewed here. The hydration products of slag are principally the same as those identified in hydrating Portland cement paste, with the additional presence of a hydrotalcite-like phase. The composition of the main hydration product, C-S-H, however, is obviously influenced by the presence of slag, and is thus different from that in hydrating Portland cement paste. It is marked by a relatively lower C/S ratio and the high contents of A substituting for S in the bridging tetrahedral of a dreierkette structure /12/. The substitution degree is dependent on the C/S ratio of C-S-H and also the amount of A available for substitution /12/. The reaction of pure slag (alkali-activated) is written as: 2. Since fly ash particles are spherical and in the same size range as portland cement, a reduction in the amount of water needed for mixing and placing concrete can be obtained. In precast concrete, this can be translated into better workability, resulting in sharp and distinctive corners and edges with a better surface appearance. This also makes it easier to fill intricate shapes and patterns. Fly ash also benefits precast concrete by reducing permeability, which is the leading cause of premature failure. The use of fly ash can result in better workability, pumpability, cohesiveness, finish, ultimate strength, and durability. The fine particles in fly ash help to reduce bleeding and segregation and improve pumpability and finishing, especially in lean mixes. 3. FINENESS MODU.

1. 1.
The pozzolanic reaction is the chemical reaction that occurs in portland cement upon the addition
of pozzolans. It is the main reaction involved in the Roman concrete invented in Ancient Rome
and used to build, for example, the Pantheon. The pozzolanic reaction converts a silica-rich
precursor with no cementing properties, to a calcium silicate, with good cementing properties.
In chemical terms, the pozzolanic reaction occurs between calcium hydroxide, also known as
portlandite (Ca(OH)2), and silicic acid (written as H4SiO4 or as Si(OH)4):
Ca(OH)2 + H4SiO4 CaH2SiO4·2 H2O
or summarized in abbreviated notation of cement chemists:
CH + SH C-S-H
The product CaH2SiO4·2 H2O is a calcium silicate hydrate, also abbreviated as C-S-H in cement
chemist notation, the hyphenation denotes the variable stoichiometry. The ratio Ca/Si, or C/S,
and the number of water molecules can vary and the above-mentioned stoichiometry may differ.
Many pozzolans may also contain aluminate, or Al(OH)4, that will react with calcium hydroxide
and water to form calcium aluminate hydrates such as C4AH13, C3AH6 or hydrogarnet, or in
combination with silica C2ASH8 or strätlingite (cement chemist notation). In the presence of
anionic groups such as sulphate, carbonate or chloride, AFm phases and AFt or ettringite phases
can form.
slag reaction
The reaction of slag in cement with and without interaction with the clinker hydration is
extensively discussed in previous works of the current authors (/4/,/5/) and is briefly reviewed
here. The hydration products of slag are principally the same as those identified in hydrating
Portland cement paste, with the additional presence of a hydrotalcite-like phase. The composition
of the main hydration product, C-S-H, however, is obviously influenced by the presence of slag,
and is thus different from that in hydrating Portland cement paste. It is marked by a relatively
lower C/S ratio and the high contents of A substituting for S in the bridging tetrahedral of a
dreierkette structure /12/. The substitution degree is dependent on the C/S ratio of C-S-H and
also the amount of A available for substitution /12/. The reaction of pure slag (alkali-activated) is
written as:
2.
Since fly ash particles are spherical and in the same size range as portland cement, a reduction in
the amount of water needed for mixing and placing concrete can be obtained. In precast concrete,
this can be translated into better workability, resulting in sharp and distinctive corners and edges
with a better surface appearance. This also makes it easier to fill intricate shapes and patterns.
Fly ash also benefits precast concrete by reducing permeability, which is the leading cause of

2. premature failure. The use of fly ash can result in better workability, pumpability, cohesiveness,
finish, ultimate strength, and durability. The fine particles in fly ash help to reduce bleeding and
segregation and improve pumpability and finishing, especially in lean mixes.
3.
FINENESS MODULUS:
a)
Weight retained
(g)
Cumulative weight retained
(g)
Cumulative percentage weightRetained
(%)
Therefore, fineness modulus of aggregate = (cumulative % retained) / 100 = (291/100) = 2.91
Fineness modulus of fine aggregate is 2.91. It means the average value of aggregate is in
between the 2nd sieve and 3rd sieve. It means the average aggregate size is in between 0.3mm to
0.6mm
b)
Weight retained
(g)
Cumulative weight retained
(g)
Cumulative percentage weightRetained
(%)
Therefore, fineness modulus of aggregate = (cumulative % retained) / 100 = (273/100) = 2.73
Fineness modulus of fine aggregate is 2.73. It means the average value of aggregate is in
between the 2nd sieve and 3rd sieve. It means the average aggregate size is in between 0.3mm to
0.6mm
so both are medium sands..Sieve size
Weight retained
(g)
Cumulative weight retained
(g)
Cumulative percentage weightRetained
(%)4.75mm151532.36mm6075151.18mm100175350.6mm105280560.3mm130410820.15mm90
500100total291

3. Solution
1.
The pozzolanic reaction is the chemical reaction that occurs in portland cement upon the addition
of pozzolans. It is the main reaction involved in the Roman concrete invented in Ancient Rome
and used to build, for example, the Pantheon. The pozzolanic reaction converts a silica-rich
precursor with no cementing properties, to a calcium silicate, with good cementing properties.
In chemical terms, the pozzolanic reaction occurs between calcium hydroxide, also known as
portlandite (Ca(OH)2), and silicic acid (written as H4SiO4 or as Si(OH)4):
Ca(OH)2 + H4SiO4 CaH2SiO4·2 H2O
or summarized in abbreviated notation of cement chemists:
CH + SH C-S-H
The product CaH2SiO4·2 H2O is a calcium silicate hydrate, also abbreviated as C-S-H in cement
chemist notation, the hyphenation denotes the variable stoichiometry. The ratio Ca/Si, or C/S,
and the number of water molecules can vary and the above-mentioned stoichiometry may differ.
Many pozzolans may also contain aluminate, or Al(OH)4, that will react with calcium hydroxide
and water to form calcium aluminate hydrates such as C4AH13, C3AH6 or hydrogarnet, or in
combination with silica C2ASH8 or strätlingite (cement chemist notation). In the presence of
anionic groups such as sulphate, carbonate or chloride, AFm phases and AFt or ettringite phases
can form.
slag reaction
The reaction of slag in cement with and without interaction with the clinker hydration is
extensively discussed in previous works of the current authors (/4/,/5/) and is briefly reviewed
here. The hydration products of slag are principally the same as those identified in hydrating
Portland cement paste, with the additional presence of a hydrotalcite-like phase. The composition
of the main hydration product, C-S-H, however, is obviously influenced by the presence of slag,
and is thus different from that in hydrating Portland cement paste. It is marked by a relatively
lower C/S ratio and the high contents of A substituting for S in the bridging tetrahedral of a
dreierkette structure /12/. The substitution degree is dependent on the C/S ratio of C-S-H and
also the amount of A available for substitution /12/. The reaction of pure slag (alkali-activated) is
written as:
2.
Since fly ash particles are spherical and in the same size range as portland cement, a reduction in
the amount of water needed for mixing and placing concrete can be obtained. In precast concrete,
this can be translated into better workability, resulting in sharp and distinctive corners and edges
with a better surface appearance. This also makes it easier to fill intricate shapes and patterns.

4. Fly ash also benefits precast concrete by reducing permeability, which is the leading cause of
premature failure. The use of fly ash can result in better workability, pumpability, cohesiveness,
finish, ultimate strength, and durability. The fine particles in fly ash help to reduce bleeding and
segregation and improve pumpability and finishing, especially in lean mixes.
3.
FINENESS MODULUS:
a)
Weight retained
(g)
Cumulative weight retained
(g)
Cumulative percentage weightRetained
(%)
Therefore, fineness modulus of aggregate = (cumulative % retained) / 100 = (291/100) = 2.91
Fineness modulus of fine aggregate is 2.91. It means the average value of aggregate is in
between the 2nd sieve and 3rd sieve. It means the average aggregate size is in between 0.3mm to
0.6mm
b)
Weight retained
(g)
Cumulative weight retained
(g)
Cumulative percentage weightRetained
(%)
Therefore, fineness modulus of aggregate = (cumulative % retained) / 100 = (273/100) = 2.73
Fineness modulus of fine aggregate is 2.73. It means the average value of aggregate is in
between the 2nd sieve and 3rd sieve. It means the average aggregate size is in between 0.3mm to
0.6mm
so both are medium sands..Sieve size
Weight retained
(g)
Cumulative weight retained
(g)
Cumulative percentage weightRetained
(%)4.75mm151532.36mm6075151.18mm100175350.6mm105280560.3mm130410820.15mm90
500100total291