Engineering Materials

Engineering Materials 1
ENGINEERING MATERIALS
A Research Paper on Materials By
Student’s Name
Name of the Professor
Institutional Affiliation
City/State
Year/Month/Day

Engineering Materials 2
1. (a)
The term setting is used when describing the process of stiffening of the cement paste. Setting
process involves the change of cement paste to a state that is rigid from fluid and it is a
phenomenon which normally occurs after 2 hours of mixing the concrete mix. The concrete
achieves stiffness to retain its shape. The setting time is the duration that the concrete mix
requires to support a specific quantity of weight without denting1.
Hardening process which is also referred to as stiffening process normally takes place after the
setting process. It is a process by which there is occurrence of hydration of silicate compounds in
concrete.
(b)
Hydration involves the reaction of the concrete with water. The paste of cement should be fully
saturated with water in order to cure the concrete properly. Concrete must be kept moist during
the process of curing so as to attain the optimal durability and strength. The concrete should be
covered with damp fabric or plastic to keep young and fresh concrete moist so as to prevent
evaporation.
After the concrete have been positioned and consolidated, it should be permitted to properly cure
so as to attain good characteristics. As the concrete gains strength and hardens, it becomes less
vulnerable, therefore, the critical time duration is the initial days and hours after being placed.
1 Chandigarh T, Civil Engineering Materials (4th edn, Tata McGraw-Hill Education 2011)
Gambhir M, Concrete Technology: Theory and Practice (2nd edn, Tata McGraw-Hill Education 2013)

Engineering Materials 3
Proper curing of concrete is normally significant since it helps in keeping it supported and also
keeping it moist2.
(c)
Some of the particular problems of concreting in hot climates as opposed to the temperature in
UK include:
Thermal cracking: Concrete can experience thermal cracking when the concrete is originally
positioned and the concrete interior is exposed to heat of hydration and heat rising from the
settlement of the concrete.
Plastic shrinkage: Hot weather conditions promotes loss of moisture and evaporation from the
surface. Plastic shrinkage takes place when the stress of shrinkage surpasses tensile strength of
the concrete hence resulting in cracks until the stress is reduced.
Poor appearance of the surface: Increase evaporation rate results in stiffening and drying of the
surface which may cause colour differences on the surface because of the different rates of
cooling and hydration.
Compressive strength: higher water requirement and high concrete temperature in hot dry
climates may result in lower strength. This also increases drying shrinkage of the concrete
hardened3.
2 Gan J, 2009. Cement and Concrete (2nd edc, CRC Press 2009)
Illston M. & Domone P, Construction Materials: Their Nature and Behaviour (3rd edn, CRC Press 2011)
3 Lamond J. & Pielert H, Significance of Tests and Properties of Concrete and Concrete-making Materials
(1st edc, ASTM International 2013)
Michael G. & Carmelo M, Concrete Solutions (2nd edc, CRC Press 2009)