Cau 3: Sau khi thi nghiem kiem tra do deo 1 loai be tong nang co luong dung vat lieu la X=3,2kg; N=1,95lit; C=5,72kg; D=13,5kg tinh cho 1 me tron. De dam bao mac be tong thiet ke can phai tang luong dung xi man glen 10%. Hay tinh lai cap phoi be tong? Ap dung cho 1 cong trinh co khoi luong su dung la 150m3 thi luong ximang se phai bo sung la bao nhieu? ρax= 3,1(tan/m3); ρan= 1000kg/m3; ρac= 2,6(tan/m3); ρad= 2,5tan/m3

Bai giai:

Me tron thu do^. deo co the tich be tong la:

Vb= x/ρx + n/ρn +c/ρc +d/ρd

    = 3,2/3,1 +1,9/1 +5,72/2,6 +13,5/2,5= 10,53(lit)

Cap phoi nhu thiet ke ban dau

X1= x.1000/Vb= 3,2.1000/10,53= 304(kg)

C1= c.1000/Vb= 5,72.1000/10,53= 543(kg)

N1= n.1000/Vb= 1,95.1000/10,53= 180(lit);

D1= d.1000/Vb= 13,5.1000/10,53= 1282(kg)

Sau khi tang 10% ximang, me thi nghiem la 10,635 lit. Cap phoi tinh lai la:

X2= 3,2.1,1.1000/10,635= 331(kg);

N2= 1,9.1000/10,635= 178,66(lit);

C2= 5,72.1000/10,635= 538(kg);

D2= 13,5.1000/10,635= 1269(kg);

Luong xi mang tang trong moi m3 be tong la:

∆x= 331-304= 27(kg);

Toan bo cong trinh  luong xi mang se tang la

∆X= 150.27= 4050(kg)= 4,050(tan)

Cau 1: Hay trinh bay su bien doi hoa ly khi say va nung dat set dung de che tao gach ngoi xay dung?

- O 100°C nuoc tu do bay hoi, chua he co cac phan ung hoa hoc xay ra.

- O 450°C cac tap chat huu co bi chay?

- O 700°C nuoc hoa hoc bi tach ra

- 800°C cac khoang vat tach thanh cac axit tu do

- 900°C canxicacbonat CaCO3 bi phan giai

CaCO3 (900°C)→ CaO + CO2

- O khoang 1000°C dat tao set chay ra lap day cac lo rong. Day la nhiet do dung ket Td (t° nung gach ngoi)

- Neu tiep tuc tang nhiet do thi nhiet do^. do’ goi la nhiet do chay Tc

Tc-Td = 100÷70°C

Cau 2: Hay trinh bay hien tuong an mon da xi mang va cac bien phap bao ve?

- Nguyen nhan:

+ Do thanh phan hoa hoc CaO

+ Thanh phan khoang vat C3A

+ Thanh phan cau truc: Neu la cau truc rong thi be mat tiep xuc lon dan den an mon nhanh

+ Van toc tiep xuc (xam thuc)

+ Nong do xam thuc

- Cac dang an mon

+ An mon nuoc ngot do qua trinh rua troi va' va dap co hoc

+ An mon axit

axit + Ca(OH)2 → muoi tan

+ An mon sunfat

muoi + Ca(OH)2 → muoi tan

+ An mon dien hoa: xay ra o vung nuoc man, nuoc len xuong

- Cac bien phap bao ve:

+ Thay doi thanh phan hoa hoc de ↓CaO

+ Thay doi thanh phan khoang vat de ↓C3A

+ Thanh doi thanh phan cau truc lam tang do^. da(.c

Cac bien phap dac biet: ngan cach VL voi moi truong bang cach op VL chong an mon hoa hoc lam giam tiep xuc MT gay an mon