scholarly journals Investigation of external sulphate attacks and moisture effects on roller-compacted concrete pavement mixes containing micro silica sand powder

2021 ◽  
Vol 1067 (1) ◽  
pp. 012007
Author(s):  
Zahraa Alaa M.A. Ali Khan ◽  
Zena K. Abbas
2021 ◽  
Vol 1021 ◽  
pp. 21-34
Author(s):  
Zahraa Alaa M.A. Ali Khan ◽  
Zena K. Abbas

Roller compacted concrete (RCC) is a special type of concrete with zero or even negative slump consistency. In this work, it had aimed to produce an RCC mix suitable for roads paving with minimum cost and better engineering properties so, different RCC mixes had prepared i.e. (M1, M2, M3, and M4) using specified percentages of micro natural silica sand powder (SSP) as partial replacement of (0%, 5%, 10%, and 20%) by weight of sulfate resistant Portland cement. Additionally, M-sand, crushed stone, filler, and water had been used. The results had obtained after 28 days of water curing. The control mix (M1) had satisfied the required f ‘c with accepted results for the other tests. M2 mix with SSP of 5% had achieved the highest results. The f ’c for sawed cubes of (10*10*10) cm had increased by 2.26% and 3.16% when tested in directions (ꓕ and //) to the direction of loading respectively. R results for sawed prisms of (38*10*10) cm had increased by 8.78% and 8.43% when tested on top and bottom faces respectively. The density had increased by 1.04% while the absorption and volume of permeable voids had decreased by 8.11% and 7.83% respectively. The UPV results had also increased by 2.44% and 0.81% for cubes and prisms respectively when compared to the control mix. M3 mix with SSP of 10% had also achieved satisfactory results when compared to the control mix.


2016 ◽  
Vol 10 (5) ◽  
pp. 194
Author(s):  
Rouholla Barati ◽  
Seyed Ali Sahaf ◽  
Mehdi Jamshidi ◽  
Alireza Razazpor

<p>Roller compacted concrete pavement (RCCP) is one of the different types of concrete pavements which is considered as a new developing technology due to its rapid installation. However, RCCP is difficult to install in high thickness; therefore, it is essential to reduce the thickness of pavement while maintaining strength. Flexural strength and fatigue resistance are the most important parameters effective on design of thick pavements. These parameters are directly related to uniaxial compressive strength of concrete. Hence, this study determines and evaluates the compressive strength of 7-day and 28-day specimens. Given the durability of concrete pavements, particularly their penetrability against water, corrosive materials and minerals, the most important parameter is to reduce water absorption of RCCP. In order to increase strength and reduce water absorption of RCCP, different additives as well as a proper mix design can be significantly effective. This study examines the effect of various mix designs and different percentages of micro silica gel on RCCP. The suggested mix design is continuous aggregation and addition of 7% micro silica gel, which increases strength and durability of RCCP.</p>


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