Browsing by Author "Shamsuddoha, M."

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EFFECT OF CRUSHING METHODS OF VOLAGONJ STONE ON STRENGTH OF CONCRETE
(R&D Wing, MIST, 2010-02) Shamsuddoha, M.; Billah, A.M.; Islam, A.B.M.T.; H.R. Kamal, Brig Gen
A comparative study was carried on Hand Crushed and Machine Crushed Volagonj stone (major rock of Bangladesh) graded between 1 in [25 mm] to 0.5 in [12.5 mm]. Stone crushed by both hand and machine were tested for abrasion value, crushing value, flakiness index, and elongation index. These stone groups were used to prepare concrete cylinders (6 in. [150 mm] diameter and 12 in. [300 mm] height) for W/C ratio ranging from 0.45 to 0.60. Hand crushed stone was showing abrasion and crushing value more than machine crushed stone by about three and one percent respectively. Machine crushed stone is flakier and elongated than hand crushed stone by about six and two percent respectively. Cylinders made with hand crushed stone showed more compressive strength than machine crushed stone with an exception of early age (1 day) and high W/C ratio (0.60). This phenomenon suggest low strength of cement matrix-aggregate interface bond firstly due to low maturity and secondly due to low strength of cement matrix to bond with aggregate.
Feasibility Of Producing Lightweight Concrete Using Indigenous Materials Without Autoclaving
(R&D Wing, MIST, 2011-02) Shamsuddoha, M.; Islam, M. M.; M. A., Noor
This research shows the feasibility and sequential approach for producing lightweight concrete without autoclaving using indigenous ingredients and appropriate technology of Bangladesh. Ingredients were mixed chronologically using trial-and-error method to reduce unit weight. Specific volume principle was utilized to observe the effect of inclusion of cement, water, sand, lime and aluminium in the mixture to achieve the goal. Molds were used to accommodate volumetric expansion of mixture. Both 50 mm and 150 mm cubic specimens were prepared for tests. Density and compressive strength were determined for specimens. Absorption capacity and thermal conductivity were also determined to get the product performance. From the results, it was seen that density and compressive decreased with increased water-cement ratio. Volumetric expansion was high for higher volume surface ratio. Finally, lightweight concrete with density, compressive strength and thermal conductivity within range of 700-1000 kg/m3, 0.5-2.0 MPa and 0.2-0.5 W/m-k respectively was produced.