Civil Engineering/Concrete Surface


Retaining Wall
Retaining Wall  

We have used aluminium form work for Retaining Wall and columns with RCC of M-40 & M-60 grades respectively. Upon deshuttering, the surface of concrete is pitted, rough and also the heat was very high. Why this happened and what should be done to achieve smooth surface? Apparently, there is no bleeding or honeycombing.

Hi Sushil,

I suspect this problem is caused by heat of hydration and possibly stripping too early? I would suggest that the aluminium forms be insulated by use of 50mm polystyrene sheets on the outside so that the surface temperature gradient to the core is reduced. And keep the forms up for 3 to 4 days if possible.

Also, try to use aggregate that is cool (kept under shade) and use ice in the mixing water. Finally use some cement replacers such as pozzalana or GGBS- this will all reduce the heat of hydration.

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Arshad Khan


I can answer any questions to do with civil and structural engineering consultancy and construction industry in East Africa and the Middle East, and specifically with the analysis and design of reinforced concrete structures. My particular expertise is in the aseismic design and optimisation of tall buildings.


Employment history: 40 years in Construction and consultancy in the UK, Kenya, Tanzania, Uganda, Ethiopia, Eritrea, South Africa, Somalia, Zambia, Austria, Bahrain, Kuwait, Doha and the U.A.E.

.Fellow of Institution of Structural Engineers (UK) .Fellow of Institution of Civil Engineers(UK) .Member of the Institution of Engineers, Kenya .Registered Engineer, ERB, Kenya .Member of the Architectural Association of Kenya (Engineers Chapter) .Chartered Engineer (UK)

•1984: International Conference on the Art and Practice of Structural Design, London •1994: 3rd Int. Kerensky Conference in Structural Engineering, Singapore •2008: International Conference on High-Rise Towers, Abu Dhabi •2013: IEK International Conference, Kisumu, Kenya

BSc, 1st Class Hons, in Building Engineering, University of Bath, UK MSc in Concrete Structures and Technology, University of London. Diploma of Imperial College, UK.

Awards and Honors
•Science Congress Special Award (for 2-seater Hovercraft - 1968) •Institution of Civil Engineers Award for outstanding performance at Bath University (1975) •Concrete Society Postgraduate study Bursary Award (1976) •Consular Representative for British High Commission, Nairobi. (1995 to 1998) •Examiner for Institution of Civil Engineers Professional Interviews, Nairobi. (1997 to 1998) •Branch Representative in Vienna for PI assessment for Inst. of Struct. Engrs. (1999 to 2010)

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