4 research outputs found
Mud-concrete block (MCB): mix design & durability characteristics
No full textMud-Concrete is a novel concept which employs a form of ‘Concrete’ produced using soil, cement and water. The initial concept of developing Mud-Concrete was to incorporate both the strength and durability of concrete into mud-based constructions to introduce a low-cost, load-bearing wall system with easy construction techniques which ensured indoor comfort while minimizing the impact on the environment. Here the fraction of soil is fulfilling the role of aggregate in the material and low quantities of cement will act as a stabilizer. Precisely the usable gravel range and the gravel percentage governs the compressive strength of the material. The considerable high-water amount is used for the hydration of cement and keep the flow of this material. This excessive water amount is enhancing its self-compacting quality, which is capable of self-consolidation, having the ability of passing, filling and being stable without the need of any external forces. Experimental test findings determined the mix proportions of Mud-Concrete block as 4% cement (minimum), fine ≤ 10% (≤ sieve size 0.425 mm), sand 55–60% (sieve size 0.425 mm ≤ sand ≤4.75 mm), gravel 30–35% (sieve size 4.75 mm ≤ gravel≤ 20 mm) and water 18% to 20% from the dry mix. Findings further confirmed that the durability of the Mud-Concrete block satisfied the required durability standards recorded in SLS 1382. Keywords: Mud-Concrete block (MCB), Mix proportion, Fraction of soil, Compressive strength, Durability, Self-compactio
Mud-concrete slab system for sustainable construction
No full textThe urgency of global climate emergency has drawn significant attention to the building industry over the last few years. Today, the building sector is responsible for 38% of the world’s greenhouse gas emissions, according to UNEP. 60% -70% of embodied carbon in a conventional column-beam reinforced concrete building is in its floor system. This paper discusses the possibility of constructing an earthen slab system using mud-concrete. It investigates a doubly curved shell structure, working predominantly in compression, to fulfil both environmental and economical demands in the construction industry; reducing the cost and labour expenses nearly 50% compared with that of traditional reinforced concrete slab systems. A 1 m x 1 m prototype mud-concrete slab was constructed to check the potential for modular construction with a square footprint. Poured mud-concrete shell of 50 mm thickness is the primary structural component, while a non-structural mud-concrete filling to a horizontal level 50 mm from apex was used to create a usable floor surface. Masonry mould method was used as the formwork system for the construction considering its cost effectiveness and ease of construction
Effect of aggregate percentage on compressive strength of self-compacting in-situ cast Mud - Concrete load bearing walls
No full textMud-Concrete is a novel concept which produces a composite material using soil, cement and water. In the concept of Mud-Concrete technology, sand and metal of concrete are replaced by fine and coarse aggregates of soil. Furthermore, precise gravel percentage governs the strength of Mud-Concrete. Unlike a block when it comes to in-situ cast wall, the walling system could provide much space to both fine and coarse gravel in the mixture, because wall could expand its vertical boundaries. Therefore finding the optimum gravel size and the gravel: sand ratio is important to achieve the best mix for in-situ cast Mud-Concrete load-bearing wall. The experimental results showed that the best gravel (sieve size 4.75mm ≤ gravel≤ 32mm): sand(sieve size 0.425mm ≤ sand ≤4.75 mm): fine (≤ sieve size 0.425mm) ratio for in-situ cast Mud-Concrete wall is 45:50:5 with minimum 4% cement. Further the results indicate the usable gravel range in the soil for Mud-Concrete construction is limited to 35%-55% and sand is limited to 60%-40% with 4% cement. The compressive strength of the Mud-Concrete depends on the particle size distribution of developed soil, optimum gravel size and the optimum gravel: sand ratio of the mix
An ATM and ATR dependent checkpoint inactivates spindle assembly by targeting CEP63
No full textThe effects of ATM and ATR signalling induced by chromosomal breakage have been
described extensively in modulating cell cycle progression up to the onset of mitosis.
However, DNA damage checkpoint responses in mitotic cells are not well understood.
This thesis reports on the effects of double strand breaks on the progression of mitosis.
We found ATM and ATR activation can occur in mitotic Xenopus laevis egg extract
and the induction of ATM and ATR by chromosomal breakages inhibits spindle
assembly in both Xenopus egg extract and somatic cells. The delay in mitotic
progression induced by ATM and ATR was found not to involve major spindle
assembly factors activities such as, Cdk1, Plx1 and RCC1/Ran-GTP. However, normal
anastral spindles formation around linear DNA coated beads, which can activate ATM
and ATR, linked centrosome-driven spindle assembly to ATM and ATR dependent
spindle defects. cDNA expression library screening was undertaken to identify novel
ATM and ATR targets in this mitotic checkpoint pathway, through which the novel
centrosomal protein XCEP63 was identified as a likely candidate. Data obtained from
depletion and reconstitution of XCEP63 in Xenopus egg extract established that normal
centrosome-driven spindle assembly requires XCEP63. Moreover, ATM and ATR
phosphorylates XCEP63 on serine 560 and promotes delocalisation from the
centrosome. ATM and ATR inhibition or addition of non-phosphorylable XCEP63
recombinant protein mutated at serine 560 prevents spindle assembly abnormalities.
These findings suggest that ATM and ATR regulate mitotic events by targeting
XCEP63 and centrosome-dependent spindle assembly. This pathway may provide
support for DNA repair processes or regulate cell survival in the presence of mitotic
DNA damage
